Storyline

Read at own risk This article contains unmarked spoilers. Players new to the game would want to avoid or be cautious toward this article.

This page details the events depicted in Subnautica in which they are meant to happen.

NOTE: that the story of the game can change during development.

Canonical Events

• The Precursor Race discovers Carar on an unknown planet and begin to study the bacterium, arriving to 4546B and setting it up as a research outpost.
• Errors in quarantine procedures cause Carar to be spread to their core worlds, which are quarantined.
• The Precursors set up several research outposts to attempt to develop a vaccine, including one on Planet 4546B. The Quarantine Enforcement Platform, the Disease Research Facility, and the Alien Thermal Plant are constructed, as well as the Alien Caches (Sparse Reef, Blood Kelp Zone, Dunes, and Ghost Canyon).
• After many tests, the Sea Emperor Leviathan species is found to have an immunity to Carar, and the Primary Containment Facility is constructed, along with the Arch Caches in various biomes. The Precursors put a Sea Emperor Leviathan inside, along with its seven eggs.
• Precursors take a Sea Dragon Leviathan egg for research on leviathan egg hatching conditions, and the parent destroys the Disease Research Facility, releasing Carar and initiating the planetary quarantine.
• The Precursors dissected one egg for testing, taking another one and putting it up for display, placing the remaining five eggs into the Incubator Device.
• Remaining Precursors are evacuated to sanctuaries where their bodies are disposed of and their minds uploaded to data hubs.
• The Sea Emperor Leviathan species is killed off due to their food source being wiped out by Carar, save for the one in containment.
• The Sea Emperor Leviathan trains Peepers to use the Alien Vent, with each Peeper carrying small amounts of Enzyme 42 to distribute among the planet.
• The Precursors are presumably killed off by Carar.
• Around 990 years later, the Degasi crashes on 4546B.
• The Degasi survivors build their bases on the Floating Island, however, due to torrential rainfall and Marguerit's persistence, they relocate to the Jelly Shroom Caves, and Marguerit uncovers a tablet.
• The Degasi survivors relocate again to the Deep Grand Reef, where Bart explains to his father and Marguerit that they are infected with something. After Marguerit brings an injured Reaper Leviathan to the base, an unspecified leviathan class creature attacked and destroyed the base. Marguerit chased the creature, intent on killing it, whilst Paul followed a light he saw, Bart managed to elude the creature and fled to the Floating Island, where he wrote his final log, and current status remains unknown.
• Almost a decade later, the Aurora crashes on 4546B, the player is knocked for three hours by a loose panel, any other surviving crew members perished during this period of unconsciousness.
• The Aurora explodes.
• After (arguably) one week, the Sunbeam picks up a distress call and comes to rescue the player.
• The Sunbeam sends the coordinates for the Mountain Island.
• The Sunbeam is destroyed by the Quarantine Enforcement Platform, which the player explores, discovering Alien Tablets, the Deactivation Terminal, and the approximate location of the Disease Research Facility.
• After exploring the Mountain Island, the player finds the Alien Arch within, and activates it, taking him to the Floating Island, where he also discovers the Degasi Seabases.
• The player goes to the Disease Research Facility, and discovers the nature of Carar and realizes that he is infected.
• After the incubation period for Carar is finished (two weeks, at this time), the coordinates for the Alien Thermal Plant are received.
• The player reaches the generator, attains the Blue Tablet, along with the Ion Battery and Ion Power Cell blueprints.
• The player reaches the Primary Containment Facility, and encounters the Sea Emperor Leviathan.
• The Sea Emperor Leviathan telepathically communicates with the player, and explains that it's eggs must be hatched in order to eradicate Carar.
• The player hatches the eggs after gathering various flora from different biomes using the Arches, and the Sea Emperor Leviathan (Babies) release the stable form of Enzyme 42, otherwise known as Baby Leviathan Enzymes. The Player interacts with the Enzymes, and is thus cured. After playing with their parent, the Babies leave the aquarium through the Arch behind the Incubator. Their parent stays behind as it is far too large to travel through the Arch, eventually it dies here, though the player never sees this.
• The player goes through the Aquarium Arch which is connected to an Arch on a suspended platform close to the Quarantine Enforcement Platform, he enters, and, now cured, is able to disable the weapon, allowing him to escape.
• The player returns to the Aurora and obtains the Rocket Launch Platform blueprint, where he eventually constructs it.
• The player enters the rocket, and activates it, blasting off from Planet 4546B.

Unspecified Events

• At an unspecified time, the Precursors obtain various relics from other alien races, including mankind, shown by the 13th century Mongolian sword held in the Primary Containment Facility.