Even if a key from a shady source initially works, it may have been purchased with stolen credit cards. When the fraud is detected, the key is often revoked, and you lose access to the game entirely. How to Get a Legitimate Subnautica Key
If it sounds too good to be true, it’s probably a Reaper Leviathan in disguise. subnautica license key.txt
If you are looking for codes to unlock doors inside the game (e.g., in the Aurora ship), these are found by playing: Captain's Quarters: Cargo Bay 3: Lab Access: Living Quarters (Cabin 1): Subnautica Wiki Even if a key from a shady source
Legitimate Steam keys can be bought from authorized retailers or third-party marketplaces like the key is often revoked