Stellaris – How to Conquer a Planet

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Stellaris isn’t all politics and spaceship combat; we also get to wage war for planets.

Unfortunately, these cool planetary invasions happen offscreen, and we only receive battle reports.

Recommended Read: How to Increase Population in Stellaris

Despite this, a hostile planet takeover is a vital game mechanic that all players will want to learn.

There are different ways to conquer a planet in Stellaris. You can either send in an orbital bombardment and assault armies or use colossus weaponry.


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How to conquer a planet in Stellaris

Do you have your eyes on the next planet you want to conquer in Stellaris?

These are the different methods you can use to conquer a planet in Stellaris:

  • Orbital Bombardment
  • Assault Armies
  • Colossus Weapons

Orbital Bombardment

When invading enemy systems, you will first need to destroy the Starbase and any fleets.

After doing this, it is time to target their beloved planets. When conquering a planet in Stellaris, it often begins with an orbital bombardment.

Beginning an orbital bombardment is easy. Move a fleet into orbit around the planet by right-clicking on it and selecting “Enter orbit.”

Once in orbit, your fleets will begin to bomb the planet from space. The damage the bombing causes is affected by the fleet’s size and orbital bombardment stance.

The larger the fleet, the more damage it puts out. Stances affect how aggressive your ships are when conducting a bombardment. There are 5 stances:

  • Selective. Reduced damage and your ships will stop if there are 21 pops left. Available to all empires.
  • Indiscriminate. Standard damage and your ships will stop the attack if there are only 11 pops left. This option is available to all empires, except those with the pacifist trait.
  • Armageddon. Bomb the planet with extreme prejudice. If you destroy all the pops, the world will become a Tomb World. This option is only available to genocidal empires.
  • Javorian Pox. Firing viruses onto the planet is about as nice as it sounds. Collateral damage to the planet is minimal and this stance will not kill mechanical pops. Like armageddon, killing the last pop will turn the planet into a tomb world.
  • Raiding. This option causes standard damage and has a chance to abduct pops from the planet. They can be enslaved, sold or even just killed. This stance will leave 1 pop alive. Only empires with the Barbaric Despoiler’s civic or Nihilistic Acquisition Ascension perk can raid.

Orbital bombardment is an easy way to weaken defenses before launching an invasion. The problem is bombardments can take a long time and can slow your momentum down during large wars.

Another issue is the destruction it causes on the planet.

If you intend to annex the planet after the war, the bombing damage will become your problem to fix. The residents of your new planet won’t be happy about it either.

Assault Armies

A faster and less destructive method of taking over planets in Stellaris; is to launch a ground invasion. This will require the use of armies.

There are two kinds of armies in Stellaris. Defense armies live on planets and cannot be moved. Assault armies traverse the galaxy in transport ships and are for hostile takeovers.

You recruit armies from any planet in your empire using the “Armies” tab.

Once recruited, the army will board a transport ship ready for war. Transport ships have no significant weaponry and will need escorting to ensure safety.

There are a huge variety of assault armies that can be unlocked. These range from basic pops, clone armies, battle droids, and even xenomorphs.

The combined strength of armies in a transport fleet gets an army strength score. Defense armies on a planet receive a garrison strength score. You can view a planet’s garrison strength by checking the “Armies” tab.

I would be lying if I said planetary invasion had deep and interesting mechanics.

The best advice for invading a planet is to have a higher strength number than the planet. If you don’t have a higher number, either recruit more assault armies or bomb the planet until you do.

To invade a planet, you need to move your assault armies into orbit around the target planet. If you haven’t already, now is a great time to check the planet’s defenses and see if your armies are up for the challenge.

Remember, if your numbers are bigger than theirs, they probably are. When ready, order your fleets to land on the planet, and the invasion will begin after a few days.

Once the invasion has begun, the rival armies will “fight.” We don’t get to see any of it, but we do get an overview by looking at the armies tab during the invasion.

If you are victorious, the planet is now conquered and is occupied by your empire for the rest of the war. If defeated, nothing changes, except you will lose most, if not all, of your assault armies.

Colossus Weapons

The final method of conquering planets in Stellaris is to wipe them off the face of the galaxy. This will require the use of Colossus weaponry. I should also mention this option is only available to owners of the Apocalypse DLC.

A colossus is a special ship that has a weapon capable of destroying an entire planet. I know what you are thinking, and the answer is yes, just like the Death Star.

To build Colossus ships, you first need to unlock the Colossus Project ascension perk in the traditions menu. A special project called Colossi will then need to be researched.

When completed, you unlock Colossus class ships, the colossal assembly yard, and one Colossus weapon.

After building a colossus, you will gain a total war casus belli on every empire in the galaxy. Conversely, all other empires will gain a “stop colossus” casus belli on you, too, so be careful.

A total war casus belli can only end in a truce or the destruction of one of the empires.

Remember, most Colossus weapons destroy the planet, along with all resources and pops.

If you are planning to take over a system, it may be beneficial to spare those planets from your super weapons. Destroyed planets produce no resources and can never be repaired.

Conquering planets in Stellaris is a simple but vital mechanic in waging war.

Take these methods into your next playthrough and experiment with them. You will find there is a lot of fun to be had waging land war in Stellaris.


That’s how to conquer a planet in Stellaris!

If you have any suggestions for this guide or questions, please let us know in the comments section. Have a great day.

Simon Neve

Simon lives in Northern Ireland with his wife and two children. When not caring for his family, Simon enjoys video games, board games, and tabletop roleplaying games. When playing isn't an option he writes about them instead.

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