The player controls Ryley Robinson, a survivor of a spaceship crash on an alien oceanic planet, which they are free to explore.

The game was released out of early access in January 2018 for macOS and Windows, with versions for PlayStation 4 and Xbox One in December 2018.

The player controls the lone survivor of the crashed spacecraft known as The Aurora, Ryley Robinson, as he is stranded on a remote ocean planet known as 4546B.

Players can collect resources and blueprints, construct tools, build bases and submersibles, and interact with the planet's wildlife.

Some of the most extreme dangers to the player include but not limited to: Crabsquids, Warpers, Mesmers, Bonesharks, Ampeels, Stalkers, Crashfish, and Leviathan-class lifeforms like the Reaper, Sea Dragon and Ghost Leviathans.

[1][2][3] The majority of the game is set underwater, with two explorable islands, and a simulated day-and-night cycle that affects visibility, along with an eclipse that happens on a frequent occasion.

Venturing deeper to find a possible vaccine, he discovers the Sea Emperor, a massive creature, who has been telepathically communicating with Ryley through the hallucinations.

In a post-credits scene, Ryley's PDA notifies him he will not be allowed to land until his debt of 1 trillion credits for the use of Alterra resources is paid off.

Subnautica was announced by Unknown Worlds Entertainment on December 17, 2013,[1] with Charlie Cleveland as the director and lead gameplay programmer, and Hugh Jeremy as the producer.

[7] Other influences included scuba diving, the filmography of James Cameron, and "just the feeling of exploring the deep, dark, alternately beautiful and terrible, ocean depths.

[10] Cleveland opted for this after reading an essay by Jamie Cheng who implemented similar philosophies into his game Don't Starve.

[8] The full version of the game was released on January 23, 2018, for macOS and Windows personal computers,[15][16] and on December 4, 2018, for PlayStation 4 and Xbox One consoles.

As the toolbox gets deeper and the shape of the end-game gets set, Subnautica will be a unique example of the ways survival can be tense, rewarding, and fun.

"[2] Marsh Davies of Rock, Paper, Shotgun praised the rewarding nature of exploring the world of Subnautica, but criticized the "arbitrariness" and lack of intuition in some of the in-game recipes.