Starbound Over The Network -

: For players on the same router, one player must launch the Starbound server from the initial game launcher. Other players join by selecting "Multiplayer," choosing their character, and entering the host’s internal IPv4 address .

: This is the simplest method for online play. You can right-click a friend in your Steam Friends List and select Join Game or use the Invite to game option. Ensure "Connect via IP" is enabled in your in-game options to facilitate some connection types. Starbound over the network

A dedicated server allows your world to stay online even when your main game is closed. How to set up a Starbound dedicated server - IONOS : For players on the same router, one