
The events of Subnautica 2 transpire on the moon Proteus, which the Cicada crashed on after an unscheduled phase gate transit from its charted course to the desert planet Zezura.
Overview
The moon orbits a gas giant (known to the native Axum as Apiary), located in the Eido-Thea System binary star system. Its mass is roughly 0.8x Earth's and it has a radius of 5570km (compared to Earth's 6671km). Despite being smaller than Earth, Proteus is more dense and has a gravity of 1.05g, approximately 5% higher gravity than Earth.
As Proteus is tidally locked to Apiary, a Proteus day and Proteus month are of equal length, at 81 hours. A Protean year is equal to 64 Earth days.
Proteus is a water world, largely covered by a salty ocean whilst the atmosphere is high in xenon. Xenon naturally has sedative effects on humans, making the surface inhospitable.
The water is rich in toxic heavy metals, giving it "the taste of blood" when consumed. The heavy metal poisoning makes it impossible for the Pioneers to survive past three-months, at which point they will be reprinted. Despite this, there is no in game mechanic that causes this to affect the player, and as of now is only a lore device. According to the databank entry of the Deepwing Brooder, the water is also especially rich in lipids, leading to naturally-occuring fatbergs.
Databank Entries
Proteus Medical Risks
Content retrieved via template: GetDatabank|Proteus Medical Risks
Distance from Earth
Content retrieved via template: GetDatabank|Distance from Earth
Gallery

Trivia
- The name Proteus is likely borrowed from Greek mythology, a sea god known for changing shape and hiding their prophetic knowledge, and from which the word "protean" is derived to mean "versatile," "mutable," or "capable of assuming many forms."