Subnautica is a 2018 action-adventure survival game created and published by Unknown Worlds Entertainment. Players control Ryley Robinson, a survivor of a spaceship crash on an alien ocean planet. The player’s main goals are to gather necessary resources, avoid dangerous plants and animals, and find a way to leave the planet.

The game was first released in early access for Windows in December 2014, macOS in June 2015, and Xbox One in May 2016. It officially left early access in January 2018 for macOS and Windows, with PlayStation 4 and Xbox One versions released in December 2018. Physical copies for consoles were published by Gearbox Publishing. Versions for Nintendo Switch, PlayStation 5, and Xbox Series X/S were released in May 2021. A Nintendo Switch 2 version came out in February 2026. Critics gave the game mostly positive reviews, and it sold over 5 million copies by January 2020.

A spin-off game, Subnautica: Below Zero, which was originally planned as extra content for the main game, was released in May 2021. A direct sequel, Subnautica 2, is expected to enter early access sometime in 2026.

Gameplay

Subnautica is a survival action-adventure game set in an open world and played from a first-person viewpoint. The player controls Ryley Robinson, the only survivor of a crashed spacecraft called The Aurora, who is stranded on a distant ocean planet named 4546B.

The main goal is to explore the ocean, survive its dangers, and complete tasks to move the story forward. Players can gather resources and blueprints, build tools, construct bases and submersibles, and interact with the planet’s wildlife. Major dangers include Crabsquids, Warpers, Mesmers, Bonesharks, Ampeels, Stalkers, Crashfish, and large creatures like the Reaper, Sea Dragon, and Ghost Leviathans.

Most of the game takes place underwater, with two islands to explore. The game has a day-and-night cycle that changes visibility, and an eclipse occurs often. When starting a new game, players choose from four difficulty modes:

• In survival mode, the player must manage health, hunger, thirst, and oxygen. If the player dies, they restart but lose some items.
• In freedom mode, the gameplay is similar to survival mode, but hunger and thirst are not tracked.
• In hardcore mode, the player cannot restart after dying. Their save file is permanently deleted, and they do not receive warnings about low oxygen.
• In creative mode, health, hunger, and thirst are not tracked. All blueprints are available, and players start with tools like a stasis rifle, Seaglide, mobile vehicle bay, and propulsion cannon. Items, bases, and vehicles do not need energy and are not damaged by deep water pressure.

The game works with VR headsets such as the HTC Vive and Oculus Rift. Players can use a keyboard, mouse, or game controller for input.

Plot

About 1,000 years before the game starts, an alien group called "the Architects" begins studying the ocean planet 4546B to find a cure for a disease called Kharaa, which has severely harmed their people. They learn that the Sea Emperor Leviathan species naturally creates a cure, called "Enzyme 42," in its digestive system. However, the only remaining member of this species is too old to make enough of the enzyme, and efforts to hatch its eggs to extract the enzyme fail. As the situation worsens and Kharaa spreads across the ocean, the Architects place 4546B under automatic quarantine and leave the planet.

Centuries later, a spaceship called the Degasi crashes on 4546B while searching for minerals. Three of its crew survive for an unknown time, but they are no longer alive or present when the game begins. Ten years later, the spaceship Aurora from the Alterra Corporation crashes on 4546B while searching for the Degasi wreck. The player-character, Ryley Robinson, is one of many Aurora crew members who escape in pods. He is knocked unconscious during landing and is the only survivor when he wakes up. He is contacted by the trading ship Sunbeam, which responds to the Aurora’s distress signal. When the Sunbeam tries to rescue Ryley, it is destroyed by a large alien weapon.

Ryley investigates and discovers the weapon is the Architects’ "Quarantine Enforcement Platform," which automatically attacks any ship trying to enter or leave the planet’s atmosphere to stop Kharaa from spreading. Ryley tries to disable the weapon, but the control panel detects that he is infected with Kharaa and ignores his commands.

Ryley explores the planet and learns about the Architects’ history through their facilities. He eventually finds the last living Sea Emperor, which is still held in an Architect containment area and can communicate through thoughts. Ryley activates a teleporter inside the Sea Emperor’s aquarium to allow its young to escape. In return, the Sea Emperor gives Ryley the recipe for an enzyme that will help its eggs hatch. Ryley uses the enzyme to hatch the eggs, and the young Sea Emperors release large amounts of Enzyme 42 into the environment, curing Ryley and all other infected organisms on 4546B. The Sea Emperor, now at peace, says goodbye to Ryley and dies.

With the planet cured, Ryley can now disable the Quarantine Enforcement Platform, build an escape rocket using blueprints from the Aurora wreck, and leave 4546B. In its final message, the Sea Emperor compares itself to Ryley before Ryley departs. The game ends here.

In a post-credits scene, Ryley’s PDA informs him he cannot land until he pays a debt of 1 trillion credits for using Alterra’s resources. The natural resources of 4546B are considered private property of Alterra.

Development

Subnautica was announced by Unknown Worlds Entertainment on December 17, 2013. Charlie Cleveland was the director and lead gameplay programmer, and Hugh Jeremy was the producer. The music was composed by Simon Chylinski.

Cleveland was greatly influenced by Minecraft. He said Minecraft changed the game industry and moved away from traditional challenge and progression-based games. The release of Minecraft happened at the same time as Unknown Worlds released Natural Selection 2. Feeling tired, the team wanted to try something new and decided to create a game like this. Other influences included scuba diving, the films of James Cameron, and the feeling of exploring the deep, dark, and sometimes beautiful or dangerous ocean. Cleveland did not see the game as a survival game at first but as an exploration game. The team also wanted to make a non-violent game without guns after the Sandy Hook school shooting.

The development team chose to use the Unity engine instead of Spark, the engine used for their previous game, Natural Selection 2. Hugh Jeremy, the producer, explained this decision because the game had different needs for the engine. He said, "Since the team does not include people working on Spark, it's not appropriate for Subnautica to use Spark. Using Unity allows Spark to develop in certain ways, while Subnautica can develop in others. Using Spark for Subnautica would be like trying to fit a square peg in a round hole."

The game does not have the traditional mission or quest structure usually found in video games. This was a deliberate choice. Cleveland said, "With intrinsic rewards, people are encouraged to do activities for their own value. If they overcome the learning period, they would find the activity enjoyable on its own." Cleveland made this choice after reading an essay by Jamie Cheng, who used similar ideas in his game Don't Starve.

Early access versions of Subnautica were released on Steam Early Access on December 16, 2014, and on Xbox One Preview on May 17, 2016. At first, the game had no hunger or thirst mechanics. After receiving feedback, especially from one player whose critique "struck home for me," the team added this system. They later found that it helped players understand the early parts of the game. The full version was released on January 23, 2018, for macOS and Windows computers, and on December 4, 2018, for PlayStation 4 and Xbox One consoles. The Nintendo Switch, PlayStation 5, and Xbox Series X/S versions, along with a spin-off called Subnautica: Below Zero, were released on May 14, 2021. Below Zero was released in early access on January 30, 2019.

In May 2025, game publisher Pladigious announced that Subnautica will be released on Android and iOS platforms on July 8, 2025. As of that date, the game has been officially launched and is available for download on both platforms. The mobile version includes the complete original game with all core modes—Survival, Freedom, and Creative—optimized for mobile play. It also features cloud saves, controller support, and a redesigned interface for touchscreen controls.

Reception

Subnautica received good reviews before it was released. Ian Birnbaum of PC Gamer called Subnautica an "underwater Minecraft," saying that "with a skilled developer leading the project and many different ocean areas to explore, it will be difficult for Subnautica to fail. As the game's tools become more advanced and the final goals are clearer, Subnautica will show how survival can be exciting, satisfying, and enjoyable." Marsh Davies of Rock, Paper, Shotgun appreciated how exploring the game's world gives rewards, but pointed out that some in-game recipes were confusing and not easy to understand.

At its release, the game had "generally positive reviews" on all platforms, according to Metacritic, a website that collects game reviews.

By January 2020, more than 5.23 million copies had been sold on all platforms.