Transport ships in Stellaris are the small, unarmed ships that carry your assault armies through space, and you will not find them in the shipyard or in the ship designer. You get them by recruiting an assault army in the Armies tab of one of your colonies, because every assault army comes with its own transport ship. The army travels inside that transport once it is in orbit, and from there you can fly it to an enemy planet and land.
All numbers and rules in this guide come from the Stellaris 4.5.2 (Cygnus) game files.
The basic idea is simple, but the game explains very little of what happens around it. A species can only support so many armies, a hostile starbase blocks every landing in its system, and even after you win the ground battle, the planet usually does not become yours until the war is over, unless you are fighting a Total War.
How to Get Transport Ships
Open any of your colonies, switch to the Armies tab and pick an army from the recruitment list. The basic Assault Army costs 100 minerals, takes 90 days to train and costs 1 energy per month after that. Almost every empire can build it from day one, since Interplanetary Expeditionary Forces is one of the starting technologies, although nomadic empires pay 50 alloys instead of the minerals and empires with biological ships pay 125 food.
With the Deploy In Orbit toggle on the colony screen switched on, new armies will go straight into orbit, and otherwise they will stay on the planet until you send them up yourself, either one by one or all at once with the Embark All button. Defense armies can never leave their planet, so they never get a transport.
The Army Hub on starbases
You can also queue armies from a starbase in one of your sectors. Its Army Hub tab trains assault armies on the colonies of that starbase’s sector, and the number of those colonies decides how many armies are built at the same time. You can leave a colony out of the Army Hub in its own Armies tab. These armies always deploy in orbit, and they will reinforce any army fleet that has Rally Troops enabled or that is gathered at that starbase.
The Army Hub is probably the easiest way to raise a large invasion force, since you do not have to click through every planet one by one. Make sure to switch on Rally Troops for your main transport fleet, and new armies will fly to it by themselves as long as there is a path.
Transport ship stats
The game designs your transport ship for you. A transport’s hull gives it 100 hull points, 100 armor and 70 evasion before its components and your empire’s modifiers are added. It moves at speed 160, which is as fast as a corvette and faster than frigates, destroyers, cruisers or battleships. It carries no weapons. Its three small utility slots are filled automatically and kept up to date with your research, and transports can carry a cloaking device as well. The ship itself costs nothing extra, so all you pay for is the army inside it.
Why transports are not in the ship designer
The transport hull is flagged as not designable in the game files, so it never appears in the ship designer or in a starbase shipyard. As such, you cannot refit transports or make them tougher by hand. The only way to get more of them is to recruit more armies.
Transports also cannot share a fleet with warships, and if you try to merge the two, the game refuses with “Cannot form a fleet which is partially transport”. You can merge transports with each other, though, and you should. Select all your army fleets, press Merge, and you will be able to move and land the whole force with one order.
How to Invade a Planet, Step by Step
Every invasion follows the same order:
- Take control of the system. Defeat the hostile starbase and take it over, because it blocks every invasion there, and beat any fleet that could sink your transports.
- Optionally, bombard the planet to weaken the defenders.
- Gather more army strength than the defenders have, merged into one transport fleet.
- Select the transport fleet, send it into orbit around the planet and give the Land Armies order. Landing takes 10 days.
- Ground combat runs until one side has no armies left. You can only retreat after 30 days.
- If you win, you occupy the planet. It usually changes owner when the war ends, depending on your claims and war goal. In a Total War, that happens as soon as you hold the whole system.
The first step is usually where wars get stuck. Your fleet has to win in space before the ground war can even start, and if that is the part you keep losing, the fleet composition guide will help you build a fleet that can actually take the system.
Apart from the starbase, the landing rules are short. The fleet has to be in orbit and made up of transports only, and you need to be at war with the planet’s owner. Pre-FTL worlds are the exception, since you can invade them without a war, but only inside your own borders. You also cannot land on a planet that is still being colonized. There is no fortification value or planetary shield that has to be broken first, so you can land as soon as the starbase is yours. If the defenders are already dead when your armies arrive, the planet is occupied without a fight.
Combat width and reserves
Not all of your armies will fight at once. Every planet has a combat width, which is the number of armies per side that can deal damage at the same time. It is 5 plus 0.2 times the planet size, with a minimum of 2, so a size 10 planet has a width of 7, a size 20 planet 9 and a size 25 planet 10. All other armies wait in the reserves and move up whenever a frontline army is destroyed or disengages.
So if you land 40 Assault Armies on a size 15 planet, eight of them fight and the other 32 refill the line. That is why strong armies matter more than raw numbers, especially on small planets. For reference, a commander with the Cyborg trait adds +2 combat width, as long as they are not also your ruler.
What decides a ground battle
Every day, each army on the frontline deals a random amount of damage within its damage range to the enemy. Armies below 50% health are picked as targets twice as often, so a damaged army tends to die quickly. Morale matters too. An army below 50% morale deals 25% less damage, an army at 0 morale deals 75% less, and a disengaged army deals only 15% of its damage. Robotic, Xenomorph, Undead and Machine Intelligence armies have no morale, so morale damage does nothing to them.
If you retreat after the first 30 days, each army has a 10% to 75% chance to be lost on the way up, depending on how damaged it is. Damaged armies will slowly recover health and morale between battles. The game files list 20% health and full morale per month, but they do not say when that applies.
Ground combat also causes collateral damage, which adds devastation and can kill pops. Since patch 4.3 it can no longer kill the last 300 pops of a planet, but armies like the Xenomorph Army (x5 collateral) or the Mega-Warform (x4) will still leave a mess behind.
How Much Army Strength You Need
Before you land, compare the army strength of your transport fleet with the strength of the defenders. The game shows both, and yours should be clearly higher. Some players only land once they have about twice the defenders’ strength, and I would say that is a good habit for anything bigger than a fresh colony, because a lost battle means losing every army you landed. The game’s own auto-invade logic is a little bit more daring and goes in at 1.5 times (more on that in the stance section).
Where the defenders come from
Defense armies are never built. They spawn from jobs and buildings on the planet:
- Soldier jobs, or Warrior Drones in gestalt empires. A Stronghold adds them, and its upgrade, the Fortress, adds more and also works as an FTL inhibitor.
- Enforcer and Telepath jobs.
- The capital building, with +4 defense armies for a Planetary Administration, +8 for a Planetary Capital and +16 for a System Capital-Complex.
- A governor with the Warden trait (+4, or +8 with Warden II).
That is why capitals and fortress worlds are so much harder to crack than a new colony. A normal Defense Army is also stronger than a basic Assault Army, with 250 health and 1.5 times the damage, and the Resilient trait or the Ground Defense Planning technology push it further.
Weakening the defenders with bombardment
Orbital bombardment damages the armies on a planet before you land, and devastation changes how much damage they take. While devastation is below 25%, defending armies only take half damage. Above 75% devastation, they take double. Additionally, assault armies always take twice as much bombardment damage as other armies, so enemy assault armies that were landed to defend a planet go down faster than its defense armies.
The trade-off is time. Bombardment is slow on big planets, Selective stops as soon as the defenders are dead, and a Planetary Shield Generator halves the damage. If the defender stacks Never Surrender, Survival of the Fittest and a Reinforcer governor on top of the shield, bombardment will barely scratch the planet. When your armies are already clearly stronger, landing straight away is usually faster.
Which Army Type to Build
Every army in Stellaris is the base army multiplied by its type. The base is 200 health, 200 morale and 1.5 to 3 damage per day. Costs below are in minerals for normal empires (nomads pay half that number in alloys, bio-ship empires 1.25 times as much food).
| Army | Damage | Health | Morale | Cost | Build time | Who can build it | Verdict |
|---|---|---|---|---|---|---|---|
| Assault Army | x1 | 200 | 200 | 100 | 90 days | Every empire except most Machine Intelligences and Wilderness | Starting army, fine as filler |
| Slave Army | x1 | 200 | 150 | 50 | 60 days | Slavery allowed, Neural Implants, enslaved pops of that species and a Slave Processing Facility | Cheapest, weak morale |
| Clone Army | x1 | 200 | 200 | 75 | 30 days | Gene Banks | Best cheap army, no pop cap |
| Perfected Clone Army | x1.5 | 300 | 300 | 100 | 30 days | Somatic Synthesization (Cloning traditions) | Excellent value |
| Robotic Assault Army | x1 | 400 | None | 150 | 90 days | Artificial Specialists, robot pops | Tough mid-game option |
| Psionic Army | x2 | 350 | 500 | 250 | 120 days | Telepathy, Latent Psionic, Psionic or Shroud-Forged pops | Strong, low collateral |
| Xenomorph Army | x2 | 400 | None | 200 | 100 days | Morphogenetic Field Mastery | Best all-rounder, wrecks planets |
| Gene Warrior Army | x2 | 500 | 500 | 300 | 150 days | Gene Seed Purification | Toughest standard organic army |
| Undead Army | x1 | 200 | None | 100 energy | 60 days | Reanimators civic with a Dread Encampment | Cheap, no pop cap |
| Hunter-Killer Army | x1 | 200 | None | 100 | 90 days | Machine Intelligence | Starting army |
| Battle Frame Army | x1.5 | 500 | None | 200 | 120 days | Machine Intelligence, Adaptive Combat Algorithms | Main machine army |
| Mega-Warform | x4 | 1200 | None | 800 | 500 days | Machine Intelligence, Biomechanics | For fortress worlds |
| Combat Android Army | x1 | 200 | 200 | 100 | 90 days | Individual Machine | Starting army |
| Advanced War Android Army | x1.5 | 500 | 300 | 200 | 120 days | Individual Machine, Adaptive Combat Algorithms | Main android army |
| Mega War Android | x4 | 1200 | 400 | 800 | 500 days | Individual Machine, Biomechanics | For fortress worlds |
Some civics, origins and events add their own armies, like Abominations, the Ember Legion, the Mimetic Strike Force, Warplings or the Wilderness Presapient Horde. If your empire gets one of them, check its stats in the recruitment list, since Warplings, for example, hit five times as hard as a basic army.
Pop cap, war exhaustion and collateral
Since patch 4.0.22, a species can support one assault army per 100 pops of that species in your empire. Clone, Perfected Clone and Undead armies are not limited by pops, and armies that are not tied to a species, like the Xenomorph Army or the Mega-Warform, do not count against one either.
Each army type also has its own war exhaustion and collateral factor. Psionic and Gene Warrior armies count three times as much war exhaustion as a basic army when they die and the two Mega armies four times as much, while Xenomorph and Perfected Clone armies count only a quarter. Xenomorphs cause five times the normal collateral damage, whereas Psionic and Perfected Clone armies cause half.
Since patch 4.3, many weapon and armor technologies also raise army damage or health. Traits like Very Strong (+40% damage), the Lithoid health bonus, army ranks and commander traits such as Heavy Hitter or Hardy help as well.
Best army for each empire type
For a normal organic empire, the Clone Army is the best value you are going to get for a long time once you have Gene Banks, because it costs 75 minerals, trains in 30 days, ignores the pop cap and counts only half the war exhaustion of a basic army. With the Cloning traditions, the Perfected Clone Army is even better for 25 minerals more.
Late in the game, I would say the Xenomorph Army is the best all-round choice if you do not care what the planet looks like afterwards. It deals double damage, ignores morale, does not count against any species and costs a quarter of the war exhaustion. If you want the planet in one piece, Psionic and Perfected Clone armies cause the least collateral damage of the regular armies. Gene Warriors are the toughest of the standard organic armies, but losing them is expensive in war exhaustion.
Robot-heavy empires get a solid mid-game option in the Robotic Assault Army. Machine Intelligences should switch to Battle Frames as soon as they can and keep a few Mega-Warforms for heavily defended worlds, but start those early, because a single one takes 500 days. Individual Machines follow the same path with their androids.
Orbital Bombardment Stances
Fleets you put into orbit around an enemy planet during a war will bombard it automatically with the fleet’s stance, unless something from the troubleshooting table below blocks it. Which stances you can choose depends on your Orbital Bombardment policy and on a few civics, origins and perks. Selective is the default.
| Stance | Damage to planet / armies | Stops killing pops at | Who can use it |
|---|---|---|---|
| Selective | 0.5 / 1.0 | 2,100 pops | Every empire not on the Devastation policy |
| Indiscriminate | 1.0 / 1.5 | 1,100 pops | Indiscriminate or Armageddon policy, not Pacifists |
| Armageddon | 1.5 / 2.0 | No floor, can create Tomb Worlds | Fanatic Purifiers, Determined Exterminators, crisis empires, Death From Above |
| Javorian Pox | 0.2 / 1.5 | No floor, spares robotic pops | Javorian Pox Sample relic plus Indiscriminate or Armageddon policy |
| Raiding | 0.5 / 0.5 | 200 pops plus 200 per army on the planet, abducts instead of killing | Nihilistic Acquisition, Barbaric Despoilers |
| Seed Bombing | 1.0 / 0.5, but the tooltip says no army damage | Never kills pops | Fruitful Partnership origin |
| Firestorm | 1.25 / 1.25 | No floor | Devastation policy or Engulfing Flames menace perk |
| Seismic Carpet Bombing | 1.5 / 2.0 | No floor | Devastation policy |
| Plundering | 1.0 / 0.25 | 200 pops, steals resources | Void Reavers civic |
| Voidworm Spores (three versions), Brood Bombing | Varies | Varies | Monsters and crises only |
The pop numbers are floors. Selective will not kill any more pops once the planet is down to 2,100, and Indiscriminate stops at 1,100. Bombardment also cannot kill pops while devastation is below 25%. That being said, heavy devastation cuts housing and jobs, so the population can still drop below those numbers.
Selective is the gentlest stance. It stops once all defense armies are dead, pauses during ground combat and will not touch undefended colonies. Keep at least one warship in orbit until your armies land, though, because the planet can rebuild its defense armies once no hostile fleet is orbiting it.
Armageddon is limited to Fanatic Purifiers and Determined Exterminators through their policy, crisis empires and anyone with the Death From Above menace perk from the Galactic Nemesis ascension perk. Older guides often add Devouring Swarm, but in 4.5.2 the Armageddon policy only lists those two civics. Scorched World Heralds and Pyromanic Instinct get the Devastation policy instead, which gives them Firestorm and Seismic Carpet Bombing but takes away Selective and Indiscriminate while it is active.
To speed things up, use a bigger fleet (each extra ship adds less once it is large), fit Siege Combat Computers and take the Overwhelming Force tradition. Bigger planets take less damage, since the game divides it by 1 plus 0.08 times the planet size. A fleet that includes a Colossus cannot bombard at all.
Planetary shields and surrender
The Planetary Shield Generator halves all bombardment damage on its planet. The Orbital Shield Generator on an orbital ring sounds similar, but it only strengthens station and defense platform shields.
A planet with no defense armies left can also surrender to your fleet, which gives you the occupation without a ground battle. Your Orbital Surrender Acceptance policy has to be Allowed, and the fleet has to use Selective or Indiscriminate, since those are the only two stances that accept a surrender. Hive Minds and Machine Intelligences never surrender, and homicidal empires can neither surrender nor accept a surrender. Unless you want to kill or abduct pops, there is little reason to keep the policy on Prohibited.
Occupation, Surrender and Peace
Winning the ground battle occupies the planet, but it does not make it yours yet, and until the war ends an occupied planet will produce nothing and you cannot build anything on it. Which planets you keep depends on your claims. The Conquer war goal is there to seize claimed systems, and a status quo peace hands both sides the occupied systems they have claimed, so in a Conquer war, an occupied planet in a system you have not claimed goes back to its owner. With one of the subjugation-type war goals, the occupied systems will instead be turned into a new subject.
Patch 4.5 changed occupation in a few ways:
- A system only counts as fully occupied if you also hold its starbase.
- In a Total War, the planets you take stay occupied until the whole system is occupied, and then you annex all of them at once.
- Since 4.5.2, making peace in one war no longer ends the occupations of a second war you are still fighting against the same empire.
Garrisons will spawn on occupied planets automatically and hold them while your assault armies move on. Max Occupation Garrisons starts at 3, and the Centralized Command technology raises it by 2. When every colony of the enemy’s main war participant is occupied, its side gains war exhaustion every month and the empire gets the Hopeless War modifier until it liberates one of them.
Losing armies is far cheaper in war exhaustion than losing ships. The game multiplies war exhaustion from lost armies by 0.25 and from lost ships by 2.0, before each army type applies its own factor, and defense armies and garrisons cause none. So throwing cheap armies at a planet mostly costs you minerals. The conquered pops are going to be unhappy for a while, too, since they get the Recently Conquered modifier (-20% happiness) for ten years.
Transport Ship Stances and Auto-Invading
Transport fleets use the same three stances as warships, but since they cannot fight, the stances work a bit differently:
- On Passive, the fleet will not move toward hostile targets, which for transports simply means they stay where you put them.
- On Aggressive, the fleet will follow friendly military fleets and invade hostile planets on its own when the odds of success are favorable.
- On Evasive, the fleet will try to return to the nearest friendly starbase as soon as hostile targets enter the system.
Aggressive saves you a lot of clicks in a long war. Put your merged transport fleet on Aggressive, send your main fleet ahead, and the transports will follow and land on planets they can take. For reference, the game files set the bar at 1.5 times the strength of the enemy ground troops, so better defended planets are left alone until you bring reinforcements and order the landing yourself.
With no weapons and only 100 base hull, transports are safer one system behind your fleet until the starbase is down. If they keep jumping out of the system every time a fight starts, check that they are not set to Evasive by mistake.
Some 4.4 versions also had a bug that split assault armies into separate transport fleets after they left a planet. Patch 4.4.5 fixed it, and if you still end up with loose transports, select them all and press Merge.
Why You Cannot Recruit Armies or Invade
Most problems with armies come down to one of a handful of rules:
| Problem | Cause | Fix |
|---|---|---|
| No assault armies in a colony’s list | The species is Exempt from military service or Tankbound | Set Full Military Service, or Soldiers Only if it is not your main species, or recruit on a planet with another species |
| “The X Species can only support Y Assault Armies” | One assault army per 100 pops of that species | Use another species, or Clone, Undead or Xenomorph armies |
| No Robotic Assault Army | Artificial Specialists missing, Robotic Workers outlawed, or robots without military service | Research the tech, change the policy, set military service for robots |
| Machine Intelligence has no Assault Army | Machine Intelligences use their own armies, unless they are Driven Assimilators or have the Shroud-Forged origin | Build Hunter-Killers or Battle Frames |
| “Hostile Starbase prevents planetary invasion” | The enemy still holds the starbase | Defeat the starbase and take it over first |
| Land Armies is not available | Not at war with the owner, the fleet is not in orbit yet, or the planet is still being colonized | Declare war first unless it is a pre-FTL world inside your borders, or wait until the fleet has arrived in orbit |
| No Land Armies order | Warships are selected together with the transports | Select the transport fleet on its own |
| Cannot invade a pre-FTL planet | Only possible inside your borders | Expand your borders first |
| Bombardment does not start | Not at war with the controller, Selective with no defenders left or ground combat running, a starbase or defense station protecting the planet, or a Colossus in the fleet | Check the war and stance, take out the station, split off the Colossus |
| Planet never surrenders | Surrender Prohibited, wrong stance, gestalt or homicidal owner, or defenders still alive | Allow surrender, use Selective or Indiscriminate, or invade |
| System not fully occupied although you hold every planet | The starbase is still enemy-held (since 4.5) | Take the starbase as well |
| Occupied planet goes back at peace | The system was not claimed | Claim the systems you want to keep |
| Transports flee when a fight starts | Evasive stance | Switch to Passive or Aggressive |
What Changed for Armies in 4.x
If you are coming back from an older version, these are the changes that matter for ground combat:
- Armies still cost no pops, and there is no manpower. You pay resources up front plus a monthly upkeep, which is energy for the regular armies, and since 4.0 empires with biological ships pay food instead of minerals.
- 4.0.22 changed the species cap from one assault army per pop to one per 100 pops.
- 4.1 moved army recruitment into the main planet window.
- 4.3 reduced defensive armies, let many technologies boost armies, slightly raised bombardment damage and kept collateral damage from killing the last 300 pops. Soldiers became specialist jobs with 1 alloy upkeep, and Siege Combat Computers now add bombardment damage.
- 4.4 added the Plundering stance, and 4.4.5 fixed armies splitting into separate transport fleets.
- 4.5 requires the starbase for full occupation and lets Total Wars annex fully occupied systems at once.
- 4.5.2 keeps occupations from a second war alive when you make peace in the first.
Conclusion
Transport ships are simply the packaging for your assault armies, so the real work in an invasion is having the right armies and taking the starbase first. In 4.5 there are no fortifications to break before you land, which means everything after the space battle comes down to army strength and combat width. If you just want to take planets with as few clicks as possible, then a merged fleet of Clone or Xenomorph armies on Aggressive, following your main fleet, is probably the way to go.
