The Mountains are a vast biome containing huge deep underwater mountain ranges, hydrothermal vents, rocky structures and an abundance of brown algae. Note that this algae cannot be scanned or interacted with. It is located northeast of Lifepod 5, bordering the Bulb Zone, one of the Mushroom Forests, the Underwater Islands, one of the Kelp Forests, and the Crater Edge.
The Mountains are characterized by a variety of huge rocky mountain ranges, sometimes with hydrothermal vents on them - Magnetite is typically found around these.
Extreme caution should be taken while exploring the Mountains, as it is home to seven Reaper Leviathans. At least one can be found near the island bordering the Mushroom Forest. These leviathans can discourage the player from going deeper into the biome, where the best fragments and areas are.
The Mountain Island, located in the southwest corner of the biome, extends 110 meters into the air above the sea level, featuring many underwater Mountains Caves that can be both entered from the underwater entrance or directly on the island's shore.
Spoiler alert: The following section contains story related material.
The foundation and underwater entrance of the Quarantine Enforcement Platform can be found on the northern side of the Mountain Island.
An Alien Vent Entrance Point is found in the Mountains, near the Mountain Island.
On the Mountains' border with the Bulb Zone, an entrance leading to the Lost River can be found.
All Data Boxes are found in Wrecks:
- In early development, the Mountains were planned to be an entrance to the Lost River.
- This was then added at one of the Mountains' borders with the Bulb Zone in the Ghost Update of 2017.