Crater Edge

Subnautica takes place inside the crater of an enormous, dormant, aquatic volcano, two kilometers in diameter. The Crater Edge 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 Crater Edge, 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 Crater Edge has a small amount of unfinished terrain at 3000 meters depth. Past that terrain there is another, seemingly infinite drop. After 8500 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, acting as the real end of the game's limit.

Description
The Crater Edge 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 Crater Edge (aka the void) at one point, but this idea was scrapped.
 * The Crater Edge was originally called The Void and the Dead Zone.
 * The Crater Edge is the deepest biome in the game.
 * The Crater Edge is one of the two biomes that do not harbor flora, the other being the Lava Lakes.