At a basic level, there are four priorities in Sins of a Solar Empire:
Every situation is unique, and as a result it is nearly impossible to develop a single strategy that will work all the time. Instead, it is important to be flexible and adapt to new and challenging circumstances. This article will discuss generalities that may or may not be applicable to your specific situation. As a player, it is up to you to decide what strategies you will use to approach your particular situation.
The first 30 minutes of the match are arguably the most important, as this is where both you and your opponent will lay the foundation of your respective empires. Larger empires can support more powerful economies, which in turn enables a larger fleet. Aside from the obvious benefit of increased income, having more planets will also give you more logistics slots. If you're colonizing fast enough, you will rarely need to purchase logistic planetary upgrades until the mid-game, another major savings. There are more than a few strategies you can use to speed up your colonization pace early on. Just remember that your enemy is out there, and you'll eventually come into contact. Ensure your military is ready for that, or your hard won empire might be taken from you. It's all too easy to become infatuated with capturing more planets and being unready for the enemy's arrival.
Colony Frigates vs Colony Capital Ships
Every faction has a colony capital ship (the Akkan Battlecruiser, the Progenitor Mothership, and the Jarrasul Evacuator) that can be upgraded with the ability to colonize planets. Although it's entirely possible to get by with only colony frigates, there are several advantages to using colony capital ships. Colony frigates are expensive, slow, and fragile. If you're using them aggressively, they're going to die and need replacing. These are unnecessary delays, and simply having a capital ship with this ability can speed things up substantially. The second and most important advantage of capital ships over colony frigates is that they have faster antimatter regeneration and a larger AM capacity. Every time you phase jump you lose 100 antimatter, which can quickly deplete a colony frigate. It can take several minutes for it to regenerate enough antimatter to colonize the planet. Capital ships regenerate antimatter much more quickly, and rarely have this problem. Time is money, and every second of delay you can cut is valuable.
Sometimes, particularly when the enemy homeworld is in close proximity, it makes more sense to lead with a more combat-oriented capital ship. In these cases, particularly if there isn't much time to colonize before the real fighting starts, there isn't as much of an advantage to using a colony capital ship. When the enemy starts further away, however, there is almost no reason not to use a colony capital ship.
The counter argument is that a colony frigate relieves the pressure on a capital ship. The capital ship can devote all of their antimatter to combat and on jumps, and the colony frigate can trail behind the capital ship using all of its antimatter for colonization. This strategy allows the capital ship to push farther without having to linger to use antimatter for colonization. Remember that all militias will always drop what they are doing and zero in on a colony ship as soon as it is in the same gravity well, so do not jump your colony ship in until the militia is all but defeated and you are confident that the colony ship can tank through all the damage that will be hurled at it. If there are no siege frigates you can get a jumpstart on colonizing, and colonize even before the other militia are defeated. This allows you to start building your colony right away. Be aware that a colony ship that is nearly full of antimatter will be able to jump into a new system and still have the antimatter to immediately colonize.
Colonize in Two Directions
There is no rule that you have to be colonizing in one direction. In fact, it's often more sensible to have your capital ship head towards planets with heavier militia while a small group of frigates clears out planets with fewer militia. If the map is generous enough, it's sometimes possible to colonize in three or even four directions simultaneously (though you might start to run into money issues and not be able to afford that kind of expansion at all). When you use many smaller groups to colonize your early empire, you take a lot of pressure off your capital ship which allows it to focus on high priority planets. Colony capital ships, in particular, can be sent far ahead of the rest of your forces to colonize and fortify strategic planets before your enemy even gets there.
All planets with economic value are defended by hostile militia that will attack anyone who enters their gravity well. If you want their planet, you will need to defeat the militia. Planetary militia are comprised of TEC units, and are always combat frigates or heavy cruisers. Here are some effective ways to defeat militia:
Know the Unit Types
There are five types of units that can be found in the militia;
Each of these units has different strengths and weaknesses, and by knowing and exploiting them you can defeat the militia more easily. The most fragile of these units is the Siege Frigate. It is also the only one capable of bombarding planets, which means after you defeat them all you can safely colonize even if the other militia are still fighting (see below for details). The Long Range Frigate packs some of the highest damage, but it's not particularly tough. Many inattentive players ignore the LR Frigate because it has long range, but taking its high damage out of the picture early is a very good idea. The Light Frigate is a lighter unit, and is usually not dangerous to capital ships. The Heavy Cruiser is a tough unit, both in terms of hit points and damage, and unless you have many bombers at your disposal, there's no right way to deal with them. The Anti-Strikecraft Frigate is a tough unit, but has low damage output. You should save it for last after the other more dangerous units are taken care of. The AS Frigate is particularly dangerous to fighters, so you may want to dock them to keep them alive if there are multiple AS. Fighters are particularly potent against the Long Range Frigate and Heavy Cruiser, but if you want to use them without getting them killed by AS Frigate you'll need to maneuver them around carefully. It's usually not practical to destroy the tough AS Frigate before the weaker units, since they are twice as tough as Long Range Frigate and Heavy Cruiser to begin with. Another alternative is to use bombers, which are more effective against Light Frigate and Heavy Cruisers and take less damage from AS Frigate.
Asteroids are always lightly defended, and have exactly one Light Frigate and one Siege Frigate. Ice and Volcanic planets have medium levels of militia; they will always have at least two Light Frigates, one AS Frigate, and one Siege Frigate. They may have additional units and could also have some Long Range Frigate, but never have Heavy Cruisers. Desert and Terran planets are more heavily defended, and always have at least one of each of the five unit types, and could potentially have dozens of units defending them. Certain custom-made maps may sport additional units or "neutral colonies" that even have turrets and hangars. However, none of the maps that come with the game by default are like this, and only a few fan-made creations use this feature. Neutral Colonies are hostile towards Pirates entering their territory, so their continued existence could (in very rare circumstances) prove useful if you have a large amount of bounty against you.
Although the militia will continue to attack you, their presence does not prevent you from colonizing the planet. You are actually capable of colonizing a planet and building turrets or other defenses while you do battle with the militia. Any Krosov Siege Frigates in the militia will move to bombard the planet, but if you destroy the Krosovs quickly enough you will maintain control of the planet. You can build turrets to help defeat the remaining militia, and build repair bays to restore your capital ship to full fighting strength. You can even move on to the next planet and leave the militia to be defeated by your turrets. Doing this usually requires a colony capital ship, since colony frigates are often too slow or fragile or simply run out of antimatter. Remember that the Javelis LRM Frigate out ranges turrets, so if there are any of these in the militia you will need to kill them before sending your capital ship or frigates away.
One of the downsides if you send your capital ship away before the militia are all defeated is that you will miss out on valuable experience. However, every second your capital ship lingers is time you could be colonizing and building your empire. Generally, advancing and gaining control of planets closer to your enemy is more important: while your capital ship may remain in the gravity well for a few minutes soaking up experience, the additional strategic advantage of another planet to defend against your enemy is usually worth a bit more than any experience your capital ship would gain.
Another variant is to colonize a planet with a single colony frigate without any backup. This technique is particularly useful for colonizing asteroids, and normally won't work if the planet has more than one Krosov in the militia. You will move a single colony frigate to the gravity well and colonize the planet. Immediately build a turret between the planet and the Krosov that is moving to bombard it. The Krosov will attempt to reposition itself outside of the turret's range, but if you place the turret close enough to the planet, the Krosov will still be within range after it finishes repositioning itself. The turret will finish construction and destroy the Krosov before it can successfully bombard the planet, and then destroy the remaining militia. Some people consider this a bug with the militia's AI, but it is frequently used in online multiplayer regardless.
Sometimes you just don't have time to deal with a planet's militia. If there are higher priority planets to capture on the other side, it may be very reasonable to completely skip the planet and move on. This is called a "bypass" and usually requires a colony capital ship (since slow colony frigates will have a hard time getting past). This enables you to move on to more strategically important planets without having to fight through time consuming and powerful militias.
Another more devious approach is called the "Ninja Colonization". In this version, you quickly kill any Krosovs in the militia, then colonize the planet before moving on. Because the militia can be tough, it might be difficult to simply build turrets and fight them that way. Instead, you simply leave the militia alone. Without siege frigates, they cannot bombard the planet and you will retain control as well as the benefit of any tax income. Furthermore, the militia will actually protect the planet against enemies who try to capture it, and you can always come back and destroy them for valuable capital ship experience later on. Still, even with very large amounts of enemy militia, it's almost always a better idea to simply invest in a few turrets to wipe them all out.
Using scouts as your primary colonization fleet is the most effective strategy to use, but is also the most difficult. Although weak individually, large numbers of scouts (10 or 11) can very quickly shred the Krosov militia. Using this strategy, first warp in all of your scouts at once, and then manually target each siege frigate in the gravity well, and then order your scouts to warp out. Except on very heavily defended planets, you will probably only suffer a few losses even if you don't micromanage your damaged scouts to retreat.
Once the siege frigates are dead and your scouts have retreated, and once your colony frigate has sufficient antimatter, send it in to colonize and then retreat. Develop the planet and build as many turrets as you need. On Ice and Volcanic planets, only one turret is necessary; on the more heavily defended Desert and Terran planets, the rule of thumb is to build a turret for each heavy cruiser and for every 2 light frigates in the gravity well. Once the turrets start firing at the militia though, make sure to priority target the heavy cruisers, which do the most damage by far. If you don't manually target the heavy cruisers, the turrets have a nasty habit of instead attacking the almost completely harmless flak frigates, which can result in the HCs destroying the turrets and regaining control of the gravity well.
If you have enough turrets, they will wipe out almost all of the enemy militia, with one exception: the LRM frigates, which outrange turrets. To destroy the LRM, one has to warp some of their scouts back in to destroy any remaining LRM.
Colony Frigate Aggro
Planetary militia will single-mindedly abandon everything they are doing to hunt any colony frigate within their gravity well. This works when the planet has not been colonized; after colonization, colony ships will be relatively low priority targets. You can use this strong behavior to your advantage. If for some reason you really need to distract or delay the militia, just warp in a colony frigate. Watch them run to the other side of the gravity well to attack it, then warp it out before it takes damage. They will then return to trying to attack your units. You can use this time to kill siege frigates or build turrets or even a starbase. By using two different phase lanes with two different colony frigates, it's possible to distract the militia long enough for a starbase to complete, which will defeat any force of militia regardless of how powerful it is. Using a starbase, you can colonize a planet without a capital ship and without taking casualties, plus you have a nifty starbase there afterwards. However, this is extremely costly, and is most likely prohibitive in the early-game: in the early-game, it would usually be better to use the next strategy (scout bait), and in the mid to late-game, it's often better to simply keep your capital ship in the gravity well neutralizing the militia for experience.
One way to buy yourself enough time to build defenses after colonizing a heavy-militia planet is to have a scout in the gravity well when the colony frigate colonizes. After the siege frigates are dead, have your colony frigate warp in, colonize, and retreat: warp out all your forces except for that one scout, and then order that scout to fly in circles around the gravity well. Your construction frigates will then be free to build extractors and turrets without interference. Once you have as many turrets as you need (at most, one for each heavy cruiser and for every 2 light frigates), have the scout warp out: the militia will then target your fully-built turrets and the militia will be destroyed. (But once the militia start targeting your turrets, don't forget to warp a few scouts back in to kill the LRM, which the turrets will be unable to attack)
First Come, First Serve
When faced with two equal priority targets, militia will keep attacking their current target. This means that if you warp in all your fleet at once, the first frigate to arrive will be the militia's target. So... if you warp in one specific unit first you can control which unit will be the militia's target. The most obvious application is to warp in a tough capital ship first so the militia will focus fire on it, then bring in the support frigates afterwards so they don't get attacked. You could also use a scout to lure the militia into a wild goose chase before warping out the gravity well. Remember that strike craft are considered high priority targets for flak frigates, LRM prefer attacking light frigates, and heavy cruisers prefer attacking scouts and LRM.
Truce amongst Rogues
The TEC rebels have a unique technology that allows them to ally with the planetary militia. It may be worth your time to simply rush this technology and send out several colony frigates to neutral planets. The frigates will meet no resistance and the militia will provide limited protection against enemy invasions, especially on heavily defended worlds such as terran planets. However this strategy does have some downsides, such as needing to make your first four research bases all civilian. You will also lose all the potential capital ship experience.
Colonization is the foundation of your empire, but you will still need to build a powerful economy on top of it. In the early game, basic tax and extractor income is often sufficient, and it's more important to put your money towards your military to expand and protect your empire. However, that tax and extractor economy won't last you the entire game. Particularly on large maps where loyalty becomes an issue, you will eventually need to move on to trade income. Higher level civic technologies which grant economic bonuses also become important, but you always need to keep a plan and build the economy that's right for your empire.
In the more competitive multiplayer games against humans, getting trade ports up as soon as possible is one of the keys to winning in longer spacious games, such as 1v1.
Tax and Extractor Income
These forms of income are based on the allegiance statistic of the planet, and are most effective on planets near your homeworld. However, as you move away from your homeworld, maximum allegiance drops, and these income levels drop accordingly. You can slightly raise allegiance with a culture structure here and there, but the underlying problem will remain.
Sometimes extractors can be found in uncolonizable gravity wells. You can capture these with colony frigates (Vasari uses their scouts instead; this is a major advantage since scouts are much cheaper and faster). Unlike normal extractors, these are unaffected by loyalty, so no matter how far away from your homeworld they are, they produce maximum income. They also benefit from refineries built nearby. Holding on to these extractors is a huge benefit, and letting your opponent control them is always a very bad thing: each neutral extractor is worth about as much as an expensive trade port!
When you decide to introduce trade into your empire, an important aspect is building your trade route. The longer your trade route, the more money each of your trade ports will produce. For instance, four trade ports built on a single planet earn 1 credit per second each (at normal game speed), but if you built them in a line along four different planets in a row, they would produce 1.3 credits per second each. This means you get a total of 5.2 credits per second rather than 4 credits per second. This bonus only gets larger as you build more trade ports and a longer trade route. As a rule of thumb, you should begin with at least a 4-planet trade route, and you should attempt to build new trade ports in positions that will expand your existing trade route. Trade ports stack indefinitely. If you build five trade ports on a planet, it produces five times as much income as one trade port would. However, as mentioned above, it's always better to build a long trade route rather than placing all your ports on one planet.
Be careful where you place your trade ports, as it's actually possible to accidentally shorten your trade route. Traders will always take the shortest route from point A to point B. This means that if you build a new trade port that opens a short-cut between point A and B, it's no longer your "longest trade route" because there's now a shortcut. Tactically, it often makes sense to avoid building trade ports on certain planets to force trade ships to take artificially longer routes.
In the original game, all uncolonizable gravity wells (including the sun) are considered to have a trade port built on them for the purposes of considering your longest trade route. This could allow you to potentially have very long routes with very few ports. With Sins of a Solar Empire: Entrenchment, this is no longer possible, and to have a trade route cross an uncolonizable gravity well you will need to build a starbase there and give it the appropriate upgrade. This is very expensive and means that trade routes usually only cross uncolonizable wells when they absolutely have to.
Note that trade routes can stretch across multiple stars if you place starbases with the appropriate upgrades on both stars' gravity wells. On large games this tactic, although expensive, can be largely beneficial.
Refineries (TEC / Vasari)
Refineries work differently from trade ports, and can boost the income of extractors in nearby gravity wells. All refineries have a 1-jump influence range in all directions, and will boost every extractor by 0.08 metal/crystal per second (regardless of loyalty or extractor upgrades). Each extractor can only be affected by up to three refineries, so they don't stack indefinitely like trade ports do. However, refineries also don't require trade routes to be effective, so your first one is at full effectiveness. Refineries are more expensive to set up than trade ports, and although they have a significant payoff, trade ports quickly surpass them if you have a decently sized trade chain. Most players prefer to build refineries on worlds that border an unusually high number of extractors, usually in the range of 12 or more: otherwise, refineries often have too high of a cost and pay off too little, which is why many players simply avoid building refineries altogether.
Resource Focus (Advent)
Resource Focus is a special mode of operation for Advent trade ports that boosts metal and crystal income in one gravity well. Unlike refineries, this effect stacks and benefits from extractor upgrades, but is also affected by loyalty. This special ability has been subject to much debate and analysis by fans, and is generally regarded as inferior to normal trade port operation.
Each faction has access to different types of civic technologies. All factions have some technologies in common, for instance technologies that improve extractor income or maximum planet population. However, each faction also has other unique technologies that other factions do not have. In general, the most useful technologies are those that require 1 or 2 civic labs to research. These are cheaper to research and require fewer labs, which is a lifesaver. Most of the higher level technologies are only useful for huge empires, and won't pay off well enough for smaller empires. They're often very powerful technologies, but there is a massive cost associated with researching them and larger empires will always get more effect. This means that the highest level civic technologies are usually reserved for team games on very large maps.
The advantage of technologies is that you can research them so long as you have enough labs. They do not require logistics slots like structures, and you don't need to capture a new planet. This makes technologies the most convenient way to boost your economy, but cost-wise they're actually the worst. You should use technologies sparingly to boost your best money-makers, but only very large empires should seriously consider researching the majority of the civic technology tree. Remember that civic labs are also very expensive; often times simply putting that money into a trade port or a population increase rather than pursuing higher level techs is a better investment.
Deciding how to build your fleet is always a difficult question. How big should it be, what type of units you should use, and what type of capital ships to lead it? Even once you've decided what kind of fleet you're going to use, there's the question of how to use it. The following section is a description of many types of fleets and support strategies you can employ. Often times it's a good idea to combine aspects of these different fleets on your own.
The Basic Combat Units
Light Frigate (no labs required)
Main article: Light Frigate
The light frigate is your basic combat unit that you can build from the start of the game. As far as combat units go, it is mediocre. In sufficient numbers light frigates can overwhelm capital ships, and against support units (including flaks and carriers) they receive a potent damage bonus that makes them more effective. However, they are countered by the long range frigate, which happens to have the best damage output in the game. Because of this, light frigates tend to die at an alarming rate in major battles. Their redeeming quality is their high mobility, and they are one of the only units that can seriously be used to "dance" around enemies and avoid attack.
Long Range Frigate (TEC: 2 / Advent: 3 / Vasari 1)
Main article: Long Range Frigate
The Long Range Frigate type unit (Javelis LRM, Illuminator Vessel, and Kanrak Assailant) has the distinction of being the best damage dealer in the game by cost. Simply put, a fleet of nothing but LRF is the fleet with the highest possible damage output. It has exceptionally long range, and they're available relatively early in the game. The LRF's damage is so high that there really isn't a hard counter, and their ability to focus fire on targets is so powerful that once the enemy has 30 or 40 you must carefully keep your capital ship out of harm's way.
The LRF unit does have a few weaknesses; it's quite vulnerable to fighters, flak frigates are good at absorbing their attacks, and heavy cruisers can beat them by attrition. However, the LRF is more than capable of killing carriers, flaks don't deal much damage to begin with, and heavy cruisers don't come until much later in the game. This greatly limits your options for countering LRF. Many players consider LRF overpowered because there is no good counter despite the fact that they actually have the highest overall stats of any unit in the game. However, the developers have only made relatively mild changes to the LRF over successive patches, indicating there aren't plans to change the unit significantly.
Flak Frigate (All: 2)
Main article: Anti-Strike Craft Frigate
Used primarily for swatting down strike craft, flak frigates are at first glance a specialized unit. However, they have two unique features that make them far more versatile. They have very low cost but very high hit points, making them ideal damage sinks to add longevity to your fleet. Many players who build their fleet primarily to outlast an enemy will lean heavily on flak frigates. Their second feature is that they are one of the only units (besides capital ships and starbases) that have multiple gun emplacements, which give them full 360 degrees of weapons coverage. They are capable of firing in all directions, something no other frigate or cruiser can do. This makes them one of the few units in the game that can reliably attack while moving, since they can shoot enemies beside or behind them just as well as those in front. Most units are incapable of attacking if the enemy isn't straight ahead of them, but the flak frigate can shoot in all directions, and this allows it unrivaled mobillity in combat.
Veteran players can use flak frigates to defeat long range frigates, using careful maneuvers to maximize the effectiveness of this unit while leaning on its incredible toughness to outlast opponents. However, the flak remains a very low-damage unit, so a LRF-based fleet can pick off any support units (including capital ships) before it can do its job. While a fleet of nothing but LRF will lose in a protracted shootout with a well-managed flak fleet, a balanced fleet can use its LRF to quickly remove any support units from the flak, then bring in the appropriate counters to clean them up. Against flak, defensive support cruisers (particularly the Iconus Guardian and Hoshiko Robotics Cruiser) work well here since the flaks have low damage to begin with, and further reducing it is very helpful.
Carrier Cruiser (TEC: 3 / Advent: 2 / Vasari: 3)
Main article: Squadron Support Cruiser
Less popular than the long range frigates, carriers make an alternative basis for your fleet. Because their strike craft can fight anywhere in the gravity well, carriers do not need to put themselves in harms way. In fact, they can be ordered to constantly move away from the enemy fleet, making them difficult to follow. By staying close to the edge of the gravity well, you can always warp them out if things go badly. Carriers can also be converted from fighter to bomber, adding to their versatility. Many players still swear by carriers, even though they don't quite pack as much punch as other unit types. Carriers with bombers are particularly effective against structures and capital ships, and great for hit-and-run strategies.
The best way to beat carrier spam is to quickly swarm the carriers with damage dealing units. The light frigate, long range frigate, and heavy cruiser all do this job quite well. The light frigate works best for this role since it's resistant to attacks from both fighters and bombers, while LRF and heavies are weak to fighters and bombers respectively. Large numbers of carriers are also vulnerable to certain capital ships with special abilities, including the Kol Battleship, the Halcyon Carrier, and the Kortul Devastator. Particularly against Vasari, which can actually shut down the weapons of all nearby fighters and bombers, this makes it a poor choice to go purely carriers. However, as part of your fleet working with other units, carriers make a great fighting force.
Heavy Cruiser (All: 5)
Main article: Heavy Combat Cruiser
When it comes to a balance of toughness and firepower, the heavy cruiser is king. It's not quite the damage dealer that long range frigates are, but it's pretty close and makes up for it with superior hull and armor. Heavy cruisers are the tanks of Sins of a Solar Empire, and their only real drawback is their weakness to bombers and their short attack range. Heavy cruisers are vulnerable to certain special abilities that can affect their ability to attack, particularly the abilities of the Iconus Guardian and Stilakus Subverter.
Non-Combat (Support) Units
Scout (no labs required)
Main article: Scout Frigate
The scout is sometimes used as a combat unit of necessity. It gets a decent damage boost against long range frigates, and prior to its nerf in Patch 1.19 was considered by many players to be a powerful combat unit as a result. However, the scout still fulfills a useful role as a fighter squad in frigate form. It doesn't deal as much damage and it's easier to kill, but if you don't have carriers it's a worthy consideration. The Advent scout has excellent shield values, and is actually worthwhile as a damage absorbing unit even to this day. The TEC scout on the other hand can be used to quickly demolish buildings, a very useful ability to take down frigate factories and cut off the enemy from reinforcements. Also, with help from other ships, scouts are a great way of getting rid of mines.
Siege Frigate (TEC: 2 / Advent: 1 / Vasari: 1)
Main article: Siege Frigate
These units are capable of bombarding planets, and this is pretty much all they're good for. Their hull points are absolutely abysmal despite their large cost. Their fragility makes them difficult to use while battle is still going on, particularly if the enemy has fighters (since siege frigates are weak to fighters). Usually a siege frigate should be used for clean-up after the battle is over, and siege capital ships should be used if you want to actually bombard during battle.
Assault Cruiser (TEC: 4 / Advent: 3 / Vasari: n/a) (Entrenchment/Diplomacy Only)
Main article: Anti-Structure Cruiser
The assault cruisers (Ogrov Torpedo Cruiser and Solanus Adjudicator) are dedicated anti-structure cruisers. The Ogrov has a single powerful attack that can shred through buildings one by one with great ease, and is particularly useful against starbases. The Advent Adjudicator has the ability to attack multiple targets at once, making it useful for taking down several targets simultaneously. Due to its increased cost and marginal survivability, the Adjudicator is usually regarded as a very poor unit choice. The Vasari do not receive an assault cruiser, and instead have a dedicated minelayer unit.
Minelayer (Vasari only: 3) (Entrenchment/Diplomacy Only)
Main article: Sivuskras Ruiner
The Vasari receive the Sivuskras Ruiner, the game's only dedicated minelaying unit. While the Advent carrier can lay mines and the TEC construction frigate can build them, these are both highly limited. Construction frigates are weak and easily killed, and take considerable amounts of time to lay even a single mine, making them useless if time is a factor. The Advent carrier requires antimatter to lay mines, which limits its ability to quickly deploy large numbers of mines and leaves it depleted for upcoming battles. The Ruiner has no such limitations, and is capable of instantly deploying mines without any strings attached. Pay the cost and the mines are deployed. This high utility makes Vasari mines the only variety that can be deployed during a battle.
Repair/Disable Support Cruiser (TEC: 3 / Vasari: 4 / Advent: 5)
Main article: Defensive Support Cruiser
The repair support cruisers are the Hoshiko Robotics Cruiser, the Serevun Overseer, and the Domina Subjugator. The Hoshiko is one of the most powerful units in the game, able to repair many units around it with great speed. It is also cheap and very tough to kill, making it a very powerful addition to any fleet. The Hoshiko is the backbone of any TEC fighting force, lowering the casualties their units sustain in battle and keeping units firing for longer. Multiple Hoshikos do not stack for effect, but can repair more targets. The Serevun is the Vasari repair cruiser; it's more expensive than the Hoshiko and not quite so good for repairing your whole fleet, but it is much better suited to dealing with enemies that focus fire. Its healing effect is instant, and also gives a temporary armor boost to further reduce damage. Multiple Serevun can be used on a single target (usually a capital ship or starbase) to continually keep its hit points high, but their armor boosting effect does not stack. The Advent Domina is by far the least effective, despite appearing the latest in the tech tree. It still fulfills a repair role (and makes it's target immune to disablement), but is typically only used for capital ships or starbases. It can, however, lock down any frigate or cruiser's abilities, construction, phase jump, and weapons. This means the superior Hoshiko is doing nothing at all, the construction frigates are not completing that turret, the scout is not scooting past your front lines, and the LRF is not killing your repair-Dominas.
Fleet Support Cruiser (TEC: 5 / Vasari: 5 / Advent: 3)
Main article: Offensive Support Cruiser
The fleet support cruisers are the Cielo Command Cruiser, the Stilakus Subverter, and the Iconus Guardian. The guardian appears earliest in the game and is among the most powerful of the three, having the ability to add essentially a second layer of shields to the entire fleet. Combined with the Progenitor Mothership to keep the Advent shields at full capacity, this can make an Advent fleet nearly unstoppable in a straight shoot-out. They also can be upgraded via research to have the repulsion ability, which can push away enemy units. Short-ranged units won't be able to attack and will be held back helplessly. This is an awesome ability to use against heavy cruisers. The Subverter is even more underhanded, and is capable of shutting down enemy units and leaving them completely helpless and held in place. Against tightly packed groups of enemies, the subverter's effects can be positively terrifying. By comparison, the Cielo is quite weak and is only marginally useful for helping take down large enemy targets like starbases and capital ships.
The case can actually be made for placing the Iconus Guardian among the Repair Cruisers, as both of its abilities have as their primary effect keeping ships alive, which is what the Hoshikos and Overseers are also primarily for. In that case, one views the Domina as a Fleet Support Cruiser for its Suppression ability.
Colony (TEC: Akkan / Advent: Progenitor / Vasari: Jarrasul)
Main article: Mothership
The colony-class capital ships are the most economically-minded of the five varieties. As discussed in the earlier section, they offer substantial advantages over ordinary colony frigates. However, the Akkan and Progenitor in particular offer extra bonuses; the Akkan gives you free structures as well as a temporary boost to the newly colonized planet's resource income, while the Progenitor offers a substantial discount to planetary upgrades purchased within a few minutes after colonization. The Jarrasul's special benefit to its colonize ability is spawning multiple construction frigates on colonization, which can be extremely useful when you want to build defenses or factories immediately in anticipation of an attack very soon. The Jarrasul also has some of the most useful other abilities, and is particularly effective at trapping and killing enemy capital ships. However, all three of these capital ships suffer the weakness of having low armor and movement speed, making them very vulnerable in large battles.
Many Sins players are of the opinion that the TEC faction needs a high level Akkan Battlecruiser with the Armistice ability to compete with the other factions in the late game. Most Advent players would probably laugh at a late-game fleet that doesn't have a Progenitor with the Shield Regeneration ability. The Vasari often use the Gravity Warhead and Nano-Disassembler abilities of the Jarrasul in conjunction to trap and kill enemy capital ships, though many others prefer to use a high-level Jarrasul on its own to terrorize enemy fringe worlds with its Drain Planet ability. This makes the colony-class capital ships some of the most well-rounded capital ships available, strong from the first minute till the last minute of the game. They make one of the best choices for first capital ship, and remain a potent choice into the late game. In spacious maps such as 5v5, these colony capital ships are almost certainly the capital ship of choice, but in competitive smaller games (such as 1v1 or 2v2), many players prefer starting with capital ships which have more firepower.
Main article: Carrier
Armed with several squads of strike craft, carriers are some of the most deadly combat capital ships available, especially when upgraded with combat-oriented abilities such as Adept Drone Anima, Scramble Bombers, or Missile Batteries. This makes them some of the most deadly rushing capital ships available. What sets them apart from carrier cruisers is that they do not require antimatter to build their strike craft, meaning they never become "tapped" and will continue to produce more fighters no matter how long the battle draws out. This is particularly important in early fights where a combination of reinforcements and repair platforms can draw out battles for significant lengths of time. The Sova in particular is a one-man army capable of attacking virtually any unit type effectively and even attacking the enemy economy directly with its embargo ability.
The Halcyon and Skirantra are usually regarded as the two most powerful capital ships in the game due to the fact that they have excellent fleet support abilities on top of their dramatic combat powers. This makes these capital ships excellent choices at any time in the game, and it's not uncommon to see late game fleets with as many as 5 or 6 of these awesome powerhouses. The Sova is more useful at the very beginning of the game, but in larger cramped games, it is often used for a devastating strategy, the Embargo rush targeting an enemy's homeworld.
Main article: Battleship
Although in theory united by their high armor, hull, and damage values, these capital ships are some of the most diverse with different roles in their respective factions. All are held back by the fact that they have minimal fleet support abilities and as combat units they're overshadowed by the masses of strike craft deployed by carriers. They also have very low antimatter regeneration rates. While the Kortul and Radiance compensate with abilities that cost relatively little antimatter, the Kol has massive antimatter requirements to fuel its abilities, relegating it to the late game after you've researched some technologies to help it out in this regard. The Radiance and Kol tend to fulfill very niche roles in their specific factions, which hurts their ability to act as generic fleet leaders that early-game capital ships need to be. The higher degree of versatility that the Kortul has made it somewhat more popular than the other battleships, though only marginally.
The Kol is used mostly as an anti-strike craft weapon with its Flak Burst ability. A few well-placed bursts can bring down huge swaths of strike craft, but unless you've researched some upgrades it can only use this ability twice before becoming depleted, and that's presuming you aren't using any of its other abilities! This makes using a Kol very difficult, but it can be very rewarding when a huge swarm of strike craft simply disintegrates after this capital ship gets through with them. The Radiance, on the other hand, is primary used to attack enemy capital ships with its Detonate Antimatter ability. This is also one of the only weapons in the game that can be used to shut down starbase special abilities. It's somewhat of a one-trick pony, but it does its trick very well. The Kortul is the most versatile of the three battleships. It has the ability to shut down strike craft (though it cannot damage them) and protect nearby allies from their attacks, and also has the ability to regenerate its own shields and attack the enemy's antimatter reserves. The Kortul is the only battleship that actually succeeds as a stand-alone combatant in the early-game, but quickly becomes outclassed by swarms of frigates in the mid-game.
Siege (TEC: Marza / Advent: Revelation / Vasari: Vulkoras)
Main article: Heavy Assault Ship
These capital ships have the highest bombard damage in the game, and the Marza and Vulkoras add to this with some of the most devastating planet-attacking special abilities. Where siege frigates are ineffective at bombarding in a combat scenario, these capital ships excel. The Revelation is a bit of an odd duck; where the Vulkoras and Marza have combat abilities and attributes that make them comparable to battleships, the Revelation's special abilities are more passive support in nature, and it also lacks any anti-planet specials until it reaches level 6 (which is uncommon to begin with). Combined with generally weak abilities (its only redeeming feature is its excellent Reverie special) the Revelation is often regarded as one of the weakest capital ships in the game. The Marza and Vulkoras, on the other hand, are viewed as devastating additions to any fleet.
The Marza in particular has some strong anti-frigate weapons, including its Radiation Bomb and Missile Barrage special abilities, and rounding that out with its brutal Raze Planet ability it's an extremely popular choice. In fact, despite the incredible weakness it has to carrier capital ships, many players still swear by the powerful Marza. The Vulkoras has less in the way of anti-frigate abilities (it's Phase Missile Swarm ability is regarded as sub-par; most spreadsheet comparisons with Radiation Bomb place this ability at one half to one quarter the power of the Marza's) but when fully upgraded with anti-planet special abilities it is the fastest bombarding weapon in the game, striking fear into enemies that their worlds will be next to disappear.
Although they are risky, siege capital ships are critical to any form of blitz-type onslaught that requires quickly breaking through enemy planets and moving on before the enemy can react. This makes them very popular both in the early-game and late-game. The Revelation is typically not regarded as a siege capital ship by players (despite the fact that it is officially listed as one) since it lacks any special abilities to help it bombard. It does, however, have the highest bombard damage of any Advent capital ship.
Main article: Support Ship
Often regarded as the weakest capital ships in the game, the support capital ships are incredibly fragile, have large antimatter requirements, generally deal relatively low damage, and their fleet support capacity is questionable. Their only redeeming qualities are their special abilities, which don't particularly stand out when compared to other capital ships. The Dunov's Shield Restore ability does not compare favorably against the Progenitor Mothership's Shield Regeneration ability, for instance. The only one of these three that's seen frequently in online multiplayer is the Rapture, which has the ability to boost the power of strike craft by being deployed near carriers, as well as greatly reducing the damage of enemy units with its Vertigo ability or reflecting their damage back at them with its Vengeance ability. Although seldom chosen early on, it's often used as a support capital ship later in the game, particularly when combined with an already-strong defensive combo like shield restore/shield projection.
The Dunov and Antorak are seen as very niche selections. They both have a few redeeming qualities, but otherwise are very similar to the Revelation capital ship. They are often named by experienced players as the weakest capital ships in the game, and are seldom chosen unless a player desperately wants one of their special abilities.
Building Your Fleet
The most important aspect when building your fleet is to consider your damage output. The best damage dealers, as described above, are the bomber, the long range frigate, and the heavy cruiser. Since the heavy cruiser is usually not an option until later in the game, this means pursuing either carriers or long range frigates early on is a very good plan. Round these choices out with the appropriate support - support cruisers, flaks, and supporting capital ships work well - and you can have a very formidable force. Simply building huge swarms of these simple high damage combination of units can take you well into the late game, particularly if you add a more advanced support cruiser later on. However, you shouldn't just consider your own units; you should always be considering what the enemy is building and what sort of fleet they have. In particular, when anticipating a battle relatively soon (or if you're in battle already), you should be building ships specifically to counter the ships of the enemy.
A good fleet for TEC might have 3 capital ships (perhaps an Akkan, a Sova, and a Marza), 60 Javelis LRM's, 20 Hoshiko Robotics Cruisers, and 10 Garda Flak Frigates. This fleet would be somewhat weak to enemy carriers, and so if you encountered a large force of carriers you'd want to phase in more Gardas and perhaps some carriers or Cobalts. A good Vasari fleet that's carrier based might be 3 capital ships (perhaps two Skirantras and a Vulkoras), 9 overseers, 3 minelayers, and 20 carrier cruisers. This fleet will deploy mines around its carriers to block the enemy's advance while using overseers to keep its capital ships at nearly-full health. An Advent fleet might use 50 Illuminator Vessels, 6 Iconus Guardians, and 4 capital ships (perhaps two Progenitors and two Halcyons). This fleet is far more specialized, relying on its capital ships to perform more functions and support. All these fleets are approximately the same size and would take approximately the same amount of time and effort to raise.
Later on, these fleets might further develop and add more complicated unit types. The TEC fleet might phase in Kodiak Heavy Cruisers, add some Percheron Light Carriers and Cielos, and perhaps bring a Kol on to the field. The Vasari might add Subverters to its force and start to focus more on its minelayers than on its carriers, shutting down enemies with the Subverters and then laying mines around them. They might add a Kortul Battleship to disrupt enemy strike craft (something the Subverters cannot do). The Advent player might simply stick with what he's doing, adding more Illuminators and Guardians for additional firepower and shield power. Each player has a very different fleet, and as time goes on that fleet will evolve based on necessity and opportunity. The Advent player might instead phase out their Illuminators in favor of a different unit type.
The most important rule is firepower; ensure your fleet has the firepower to threaten the enemy and it's probably a decent fleet. The exact type of firepower doesn't really matter so long as you have the ability to threaten the enemy. If you don't have enough firepower to threaten the enemy, you're probably going to forced to take cover under a friendly starbase until you can build up additional forces, and in that time your enemy has free rein to attack anything else.
A difficult, even agonizing, decision is to decide how big your fleet should be. A bigger fleet is more powerful, but it increases your upkeep level and costs you more to assemble it in the first place. Against humans, there's really no right answer to this question, though there's a point at which your fleet is definitely too small to fight the enemy. In general, you should avoid being outnumbered more than 4:3, and that means you shouldn't be more than one fleet level behind your opponent. There are some strategies to overcome this without raising your fleet level, but most involve risky use of starbases or very vicious offensive tactics to keep the enemy pinned down. It's very possible to win in most AI matches by leaving nearly all supply upgrades to the late game, by utilizing upgraded starbases and repair units - this allows you to research and fortify to your heart's content without losing income efficiency. The cost, of course, is that further expansion into enemy territory becomes almost completely impossible. Using this strategy against competent human players is suicide, though, because they will simply fight your pitiful fleet outside the range of your starbases and subsequently take control of the gravity well (and the rest of your territory soon afterwards). Once you've purchased a new fleet level, you should strive to fill it as quickly as possible and keep it filled. If you're taking casualties faster than you can replace them, this either means you're fighting one intense battle or your fleet size is too large for you to sustain. If your opponent isn't having the same problem, you could actually lose the match very quickly in this situation.
A lot of the time, it's not how big your empire may be or how powerful your fleet is, it's how you use it. It's entirely possible for a smaller force or weaker empire to defeat a larger one by good use of position. This topic is mostly about distance and timing. Unless your opponent is Vasari, in which case they can deploy Phase Stabilizers to allow them to cover great distances, they cannot be everywhere at once. No matter how powerful a fleet is, it has to be in one place at any given time. You cannot protect every location at the same time. While the AI will often fall victim to a well-built starbase defense, a human player is far more cunning and you'll need to use your fleet to counter theirs. Vasari players have the biggest advantage in this area. In addition to Phase Stabilizers, they have the greatest phase jump detection technology. Also, they can use just Subverters in combination with a powerful Orkulus to shut down and then destroy an entire enemy fleet, without needing to build or move a significant fleet of their own. This is a difficult and risky tactic to carry out successfully, though, requiring constant micromanagement of your Subverters.
Sometimes, planets are important choke points, and act either as the fastest or the only pathway between two locations. Controlling a choke point enables your fleet to freely pass through it to attack or defend locations on the other side, but inhibits the enemy's ability to do the same. There are two types of choke points: lateral choke points, and forward choke points.
A lateral choke point gives you an alternate approach between two locations, but the enemy doesn't actually need to go through it to attack your empire. For instance, a lateral choke might be a shortcut between your two front lines. The enemy must maintain two fleets to attack both sides, but because your shortcut you can defend both sides with only one fleet. The same is true in reverse, the enemy requires two fleets to defend both sides but you are free to assemble your one fleet to attack one side in full force.
A forward choke point blocks access to your other planets, forcing the enemy to either fight their way through, go around and find a different access point, or to run past your defensive line. None of these are pleasant alternatives. The AI in particular can be stumped by a well fortified forward choke point.
In the early game, you should strive to identify choke points (lateral choke points are sometimes harder to spot and you only notice them after the battle lines are drawn). It's often worthwhile to grab these planets at the expense of more economically valuable ones. Controlling a choke point early on can give you a substantial military advantage, and it's always easier to hold on to them if you get there first and build some defenses. Above all, remember to use your choke points. Remember that you can easily deploy units across that choke point but the enemy cannot. This allows you to outmaneuver their forces and more easily find opportunities to attack in full force.
While the AI is notorious for its ability to charge head-first into a starbase, most human players are far more reserved. They would much rather prefer to attack the starbase from afar, or perhaps to attack a different target altogether. A starbase in this sense is more of a speedbump than a bulwark. However, when you have a fleet on guard, it can be very difficult (if not practically impossible) to take down a starbase, and an enemy will be forced to pick other targets. The goal of the starbase is to give you a safe haven, a location the enemy cannot reasonably attack you. So long as you know your own forces are close enough to your starbase, you're free to attack anywhere you want and you can always retreat to safety if the enemy arrives in force. In this way, placing starbases on lateral and forward choke points allows you to control them with ease while the enemy is forced to move around them. This allows you to better use a single cohesive fleet to fight on multiple fronts while the enemy is forced to either fight you on your own terms or to split up their fleet to compensate.
Sometimes, the best defense is a good offense. Instead of defending a weak flank, you may choose to attack the enemy. In the best case, this could distract their forces and prevent them from attack you where you're weak. In the worst case, both sides could go on a relentless attack-spree and destroy the other's empire. This mutual destruction can wipe out 90% of each empire, with both economies destroyed. However, often times planets with starbases and a few tactical defenders can survive the onslaught, as an enemy decides it's not worth getting their fleet killed to take down these positions. When the dust settles, controlling these planets can be key to winning the entire match, allowing you to rebuild an empire.
In this way, creative use of starbases and choke points can allow you to defeat fleets that are larger than your own. However, you must be careful, if the enemy fleet is too large they can just steamroll your starbases or worse, just run straight past them and attack your economic worlds in the back. If your fleet isn't strong enough to drive them out, you could be in serious trouble. An AI will seldom do this, so once you have a good starbase line in play, it's actually very easy to win regardless of the AI's difficulty level.
Location Location Location
This cannot be stressed enough: you must know where the enemy fleet is at all times. Defenses, including starbases, can only do so much to stop an offensive. If you get caught off guard and your fleet isn't in position to defend, it could already be too late. You can do the same thing to the enemy by paying attention to their fleet's position, and if they move out of line you can press your attack in a location where they are weak. Don't be afraid to retreat if they show up in force, and in fact because you know how far away they are you can be ready to fall back when this happens. Players who understand this will often run circles around their opponents with smaller forces, attempting to overwhelm one large force without ever taking it on in a straight fight. To counter this, you must know where their forces are and have your own units in position to deal with them.
Using smaller forces to beat a larger force is often called a "bait and switch" strategy. This strategy usually requires good choke points with starbases. The goal of this strategy is to have two fleets assembled on two different fronts. Any time you encounter the enemy's full fleet, you will simply retreat back to your starbases and refuse to engage them. As soon as the enemy fleet leaves, you come back and begin attacking again. In this way, it can be extremely difficult (if not outright impossible) for the enemy to defend their empire with a single fleet. As soon as they turn their back on one force, it returns to attacking them.