This article is about the Grand Reef. You may be looking for the Deep Grand Reef, the Grand Reef Caves, or the Sea Treader's Path.
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This article contains information that is updated for the latest Experimental Version of Subnautica. Players using stable mode may find this information inaccurate.

The Grand Reef is a unique deep biome in Subnautica that covers between the southwestern and southern portions of the map.

Description Edit

The Grand Reef is home to many types of fauna, including the large herbivorous Sea Treader and also two Ghost Leviathans. It is also known for its unique types of flora, from the luminous Floating Stones to the peculiar Membrain Trees. It also features its own cave system, the Grand Reef Caves.

Below this area, the player can find a large cavern system featuring the similar types of flora and fauna, with the addition of Crabsquids and Jellyrays and the absence of the Sea Treader. Above the Grand Reef is the Floating Island, which occasionally casts a large dominating shadow on the seabed.

Commonly found harvesting nodes in the Grand Reef are basalt outcrops, as well as many other types of rare crystals.

An Alien Pipe Entrance Point is found in the Grand Reef.

Scattered deep within the Grand Reef are five hydrothermal vents.


For a more complete gallery, visit Grand Reef/Gallery.


  • 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. 
  • The Grand Reef is the third biggest biome in Subnautica.
  • The Grand Reef was planned to house a Warp Gate Cache that linked to the Primary Containment Facility. This however, was scrapped.


  1. (Dated January 14, 2016)