Knowing how to expand your borders is paramount to ensuring your empire’s survival. Expanding your borders is most important in the early game.
Border disputes over resources, planets, and choke points are commonplace throughout all playthroughs.
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Failure to take the correct opportunities when it comes to expansion will lead to stagnation. A stagnant empire is doomed to defeat.
You can expand your borders in Stellaris by building outposts, making claims, and then going to war, integrating vassals, and trading for systems.
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How to Expand Your Borders in Stellaris
The early-game and mid-game are very expansion focussed. You want to be claiming all the best territories before your opponents get the chance. If you don’t beat them, well, you can always take it from them.
Building Outposts
By far, the easiest method is to find an unclaimed system and build one of your outposts there. An outpost is the space version of sticking a flag in the ground and declaring it your own.
Outposts are very cheap and take almost no time to construct. The base cost for outposts is 100 alloys and some influence. The influence cost has a base of 75.
The base cost is then multiplied by how many hyperlane jumps from your borders the new outpost is. For example, building an outpost 3 jumps away would cost; 100 alloys and 225 influence.
Before you can build an outpost, a system must be fully surveyed by a science ship. If you see another empire surveying a system you want, you will want to try and move your civilian ships in fast to secure it first. Failure to secure the planet will result in you needing to use one of the methods below.
Expansion Warfare
Another empire will inevitably lay claim to territory before you can. If your empire is not above a bit of warfare, you can lay claims to the systems you want and then fight for them.
Using the claims menu, we can put a claim on the systems we want. Placing a claim has a base cost of 50 influence and is modified by a lot of factors.
The distance to the system, if the outpost has been upgraded, the system contains a colonized planet, if it belongs to a rival, and if you are already at war.
Once you have claims, you gain the Conquer Cassus Belli on the owner of the system. If you declare this as your war goal and win the war; you take control of all the systems you had claims on.
Declaring war like this too often will attract the ire of your other neighbors. They will view you as a threat, and this will harm your diplomatic relations with them.
Integrating Vassals
Contrary to popular belief, there are peaceful ways to expand your borders too. There’s the quick way and the slow way. Integrating your vassals is the slow way.
As the game goes on, you may find yourself with one or more vassals. These are mostly autonomous empires that you have a vassal contract with. This contract may provide you with a tribute or make you obliged to protect them from galactic threats.
This contract may also give you the option to integrate the vassal into your empire. This process carries a high influence cost and takes many years. When completed, all your vassal’s systems, resources, pops, and planets become yours.
Trading for Systems
The much faster peaceful option is to use the diplomacy option called “Transfer System.” This is only available when both empires are at peace.
The AI considers this the most valuable trade resource. Securing trade deals for systems will almost always cost a large amount of resources. Having a great relationship with the empire in question is the best way to bring the likely extortionate cost down.
If they accept, the system is immediately transferred to your control.
Whether through peaceful means or military might, your empire has the power to expand. Be careful not to get overzealous when expanding. Other empires will be looking to expand their borders, and if you fail to secure them; they will not hesitate to exploit your weaknesses.
You now know how to expand your borders in Stellaris. If you have any suggestions or questions about this guide, please put them in the comment section below. Thank you for reading.