Hey, that Planet's Already Inhabited!

More about Colonization

Playing Stars!

You can't colonize a planet that's already inhabited. Colonizing means to make an uninhabited planet your own. If you transfer the colonists using Transport orders, you'll automatically initiate ground combat with the current inhabitants. At this point your colonists become ground troops. If more than one player lands ground troops on the planet during the same year/turn, everyone will fight until only one side is left.

You cannot invade any planet that has a starbase in orbit. This means you'll need to destroy any starbase with your war armada before you can beam down.

Alternate Reality Races and Invasion
Since Alternate Reality races inhabit starbases and not planets, destroying their starbase makes the planet open for colonization. Alternate Reality races also cannot invade other player's worlds.