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This article is about the Grand Reef. If this is not what you are looking for, see Grand Reef (Disambiguation).

The Grand Reef is a deep biome in Subnautica which covers a large area in the southern portion of The Crater.


The Grand Reef is home to a limited amount of fauna, including the large bottom-dwelling Sea Treader Leviathans, as well as two massive Ghost Leviathans. It is also known for its unique types of flora, from the many luminous Anchor Pods to the peculiar Membrain Trees. There are multiple entrances to small caves known as the Grand Reef Caves in the Grand Reef. Scattered deep within the Grand Reef are multiple hydrothermal vents.

Below this area, the player can find the Deep Grand Reef, a large system of caverns featuring similar types of flora and fauna, with the addition of Crabsquids and Jellyrays and the absence of the Sea Treader Leviathans.

Rubies and Gel Sacks are commonly found in the Grand Reef, along with many other rare materials and fragments. Due to the abundance of hazardous fauna, depth, and general difficulty of navigation, exploring this biome early on without adequate gear is not recommended.

An easy way to get to this biome is to use the Floating Island as a landmark for its location.

Spoiler alert: This section will reveal story-related material if expanded.

One of the five Sea Emperor Juveniles can be found here after the Sea Emperor Leviathan Eggs have been hatched. A Degasi Seabase can also be found in the deep section of this biome.



  • In earlier builds, the Grand Reef had large pillar-like spikes, some of which were visible above the surface. These were removed and was explained to be temporary. However, the concept of them may have been used for inspiration of the Crag Field. Another reason for their removal is that they had bad models and were not destructible.[1]
  • Certain structures have curious house-like caverns, very reminiscent of grotto-homes in primitive cultures.
    • There used to be several of these large "buildings", however they were removed during development.
  • The Grand Reef is the third largest biome in Subnautica.
  • There are actually only 3 types of Flora in the Grand Reef: Anchor Pods, Gel sacks, and Membrain Trees. There are numerous species of unnamed seagrasses however which serve only as decoration.
  • The Grand Reef is the only biome in the game to house two different leviathans: The Ghost Leviathan and the Sea Treader Leviathan.

Spoiler alert: The following section contains story related material.


  1. (Dated January 14, 2016)