Platforms
Short answer
Available: PC (Steam, Epic Games Store, Microsoft Store), Xbox Series X|S, ROG Xbox Ally.
Details
Available: PC (Steam, Epic Games Store, Microsoft Store), Xbox Series X|S, ROG Xbox Ally. Not available: PlayStation 5, Nintendo Switch / Switch 2, VR. Subnautica 2 is Xbox Play Anywhere — one purchase covers Xbox + PC Microsoft Store.