Co-op play

Subnautica 2 Multiplayer

Subnautica 2 supports solo play and online co-op. Official listings also point to cross-platform multiplayer.

Quick answer: Subnautica 2 supports online co-op for up to 4 players. Steam lists cross-platform multiplayer, and Xbox Wire confirms players can invite friends across PC and Xbox. There is no local split-screen co-op.

Deep sea exploration scene with submersibles and glowing underwater structures

Solo play

4-player online co-op

Cross-platform multiplayer

Recommended co-op flow

Pick one player to manage base layout and storage.
Keep one explorer near the edge of known areas, not alone in deep zones.
Use a shared material target before every dive.
Bring backup power and emergency supplies before pushing into new biomes.

Divers and a maintenance robot near an underwater habitat corridor

Shared route

Move through base exits with a clear return plan.

Explorer with a scanner, drone, and submersible in a glowing underwater reef

Scout role

One player scans and marks the next safe path.