Crater Edge

Subnautica takes place inside the crater of an enormous, dormant, aquatic volcano, two kilometers in diameter. The Dead Zone is the area surrounding this crater. With no resources and extreme danger, the zone serves as a border for the game's map.

Multiple adult Ghost Leviathans live in the Dead Zone, where they deter players from straying outside of the playable area. Up to three of these intensely territorial creatures can appear at once, only retreating when the player leaves the zone.

The Dead Zone has a small amount of unfinished terrain at 3000 meters depth. Past that terrain there is another, seemingly infinite drop. After about 8000 meters depth, the player teleports back to Lifepod 5. At approximately 4000 horizontal meters away from the map center, the zone ends. Leviathans cease spawning and there is only empty ocean.

Description
The Dead Zone is a large open ocean devoid of any flora, coral, and all but one fauna species.

Fauna

 * Ghost Leviathan

Trivia

 * Sea Dragon Leviathans, Reaper Leviathans, and other fauna, were planned to spawn in the Dead Zone at one point, but this idea was scrapped.
 * The Dead Zone was originally called The Void and the Crater Edge.
 * The Dead Zone is the deepest biome in the game.
 * The Dead Zone is one of the two biomes that do not harbor flora, the other being the Lava Lakes.