A deep-space vessel constructed by the trans-gov Alterra, known as the Aurora, has been sent to a system at the outer reaches of known space on its maiden voyage. Subnautica takes place in the late 22nd century, when humanity begins to colonize other star systems. The game officially supports VR headsets such as the HTC Vive and the Oculus Rift with the additional input of a keyboard and mouse or game controller according to the Steam sale page of the game. 'Creative Mode', in which the hunger, thirst, health, and oxygen features are all disabled, all the crafting blueprints are acquired, where no resources are needed to craft and the submersibles do not need energy and cannot be damaged. 'Hardcore mode', which is the same as Survival, except that if the player dies, the player will no longer be able to respawn and the save file is permanently deleted.

'Freedom mode', a mode similar in concept to Survival mode, but with hunger and thirst being disabled. If the player dies, certain items are lost from their inventory. 'Survival', the player will have to maintain nutrition, hydration, and oxygen. Upon beginning a new game, players must select a difficulty mode from the following four: The majority of the game is set underwater, with two explorable islands, and a simulated day-and-night cycle that affects visibility. Subnautica allows the player to collect resources, construct tools, bases, and submersibles, and interact with the planet's wildlife. The main objective of the player is to explore the ocean and survive its dangers, while at the same time completing tasks that function to advance the plot. The player controls the lone survivor of a waylaid spacecraft called the Aurora, now stranded on a remote ocean planet named simply '4546B'. Subnautica is a survival, adventure game set in an open world environment and played from a first-person perspective.

Subnautica has a sequel called Subnautica: Below Zero which launched into early access on January 30, 2019.

The full release out of early access was in January 2018, exclusively for Microsoft Windows on Steam, and later on the Discord and Epic Games stores, with the versions for the Xbox One and PlayStation 4 on December 4, 2018. Subnautica was first released in early access for Microsoft Windows in December 2014, Mac OS X in June 2015, and for Xbox One in May 2016. They will face creatures of all kinds in a battle for survival. It allows the player to freely explore the ocean on an alien planet, known as planet 4546B, collecting unique resources to survive. Subnautica is an open-world survival action-adventure video game developed and published by Unknown Worlds Entertainment.

Subnautica below zero gameplay