Subnautica is an underwater adventure game set on an alien ocean planet. A massive, open world full of wonder and peril awaits you! Dive Into a Vast Underwater World You have crash-landed on an alien ocean world, and the only way to go is down. Subnautica's oceans range from sun drenched shallow coral reefs to treacherous deep-sea trenches, lava fields, and bio-luminescent underwater rivers. Manage your oxygen supply as you explore kelp forests, plateaus, reefs, and winding cave systems. The ...