Subnautica Wiki
Spoiler (BZ) 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 article is about the Primary Containment Facility. You may be looking for the Disease Research Facility.


Translating local alien broadcast... WARNING: Vaccine development program terminated. Emperor egg hatching project terminated. Live specimens terminated. Evacuate immediately.

― PDA, Dialogue


The Primary Containment Facility, also known as the Emperor Containment Facility, Sea Emperor Prison or merely the Prison, is an Alien Base located within the Lava Lakes that serves as the final major story location. It was built by the Precursor Race around one thousand years ago and is home to the last remaining Sea Emperor Leviathan, along with the five remaining Sea Emperor Leviathan Eggs. There are two entrances to the Lava Lakes containing the Primary Containment Facility; co-ordinates are -300 -1270 -150 and 90 -1240 360, southeast, and directly north of the Lava Castle, respectively.

The Primary Containment Facility requires the Blue Tablet to unlock, which is found in the Alien Thermal Plant. An additional Blue Tablet is required to gain access to the Moonpool and subsequently the Sea Emperor.

The Primary Containment Facility, like the other Alien Bases, was built a little under one thousand years ago. Five Sonic Deterrent devices can be found in the area around the base, preventing attacks on the facility from the native fauna. It was built to contain the Sea Emperor Leviathan after it was discovered that it was immune to the Kharaa Bacterium. The aquarium section was originally all inorganic with two Alien Arches set up inside, one leading back into the Antechamber's moonpool and another leading to just outside the Quarantine Enforcement Platform. However, as creatures began migrating into it via the Arches, they brought with them flora seeds along with loose sand and mud. Over time, the aquarium became a thriving ecosystem with the Sea Emperor Leviathan at the heart. Five of the eggs that the Sea Emperor Leviathan was found with were placed in the Incubator Device to stimulate the hatching process as it was deduced that the young would be a more viable source of the cure, rather than their parent who was weak. However, the aquarium was not a suitable environment for the eggs to hatch, rather built to match the ideal environment for an adult Sea Emperor Leviathan, which differ from the ideal conditions for a juvenile Emperor, causing the eggs to go into a form of natural stasis for a seemingly indefinite amount of time, kept alive by the Incubator.




The first room in the Primary Containment Facility. It is huge and roughly octagonal in shape. A large pillar, called the Ion Cube Fabricator, lies in the center of the chamber, which is used to create Large Ion Cube Deposits. Every time the deposit on it is completely depleted the pillar will rise up and, after 2 minutes, fabricate a new deposit, after which the pillar will lower back down. Around this pillar are cases containing the Alien Relics, five on each side. There are six doorways around the sidewalls of the Antechamber, the four doors positioned at diagonals lead to Arch rooms, the middle left door leading to the "Pipe Room", and the right to the "Egg Laboratory". Accessed by ramps on either side of the entrance to the facility, another doorway can be seen, this door leads to the "Dissection Lab". At the far end of the Antechamber is another door blocked by a force field that leads to the Moonpool Room, along with its respective Forcefield Control, requiring a Blue Tablet. The Antechamber also has many specimen cases containing artifacts the Precursors collected, most originating from other alien races.



Alien Relics

A collection of eleven relics are kept in the Primary Containment Facility, with one of human origin, some of Precursor origin, but most from other, unidentified alien species. Further information on these relics can be found here: Alien Relics.

Egg Laboratory


Egg Laboratory

(for images see gallery) This laboratory is accessed through the middle door on the right side of the antechamber. The purpose of this laboratory was to study the hatching processes of local life form's eggs in order to find out how to hatch the Sea Emperor Leviathan eggs. As such, the laboratory contains many eggs from the local life forms, forty-three eggs are kept here in total, including one Sea Emperor Leviathan egg and two Sea Dragon Leviathan eggs. The unimplemented Shuttlebug egg can also be found in this room.

Pipe Room


Pipe Room

(for images see gallery) Although this room is not huge, the pipes originating from it cover tens of thousands of meters. This room's purpose is to pump cool, oxygen-rich water from the surface biomes into the aquarium, and remove the oxygen-deprived water, maintaining a stable environment for the Sea Emperor Leviathan. This room also contains five small aquariums that are filled with various coral and flora species, these aquariums have pipe exits in them so are presumably for the purpose of enriching the circulating water with plant and coral matter. The Sea Emperor Leviathan using its telepathic abilities trained Peepers to use the pipe system to distribute Enzyme 42 to the surface biomes, keeping a small amount of life on the planet alive.

Many variants of Flora and Coral can be found inside the aquariums, though they are unreachable through normal means.

Dissection Lab


Dissection Lab

(for images see gallery) This small room contains one Sea Emperor Leviathan egg that has been forcibly opened, as well as a dead Sea Emperor Leviathan fetus on a dissection table. Scanning these items reveals that the Precursors were desperate in trying to obtain Enzyme 42 when their attempts to naturally coax the eggs to hatch failed, forcing them to dissect one of the extremely valuable eggs.

Moonpool Room


Moonpool Room

A large room accessed through a door at the far end of the Antechamber, the main point of interest in this room is the large Moonpool from which it draws its name. The Moonpool leads to an observation platform above the Sea Emperor Leviathan's Aquarium, suspended by four cables, where the player will come face to face with the Sea Emperor Leviathan for the first time. At the far end of this room is a platform with an Alien Arch on it, the platform cannot be accessed from the Moonpool Room, only being accessible through an Arch in the Aquarium.

The Moonpool Room cannot be accessed unless the forcefield securing the entrance has been disabled, which can be done using a Blue Tablet at a control, located in the Antechamber.



Sea Emperor's Aquarium

The main feature of the Primary Containment Facility; a huge aquarium containing the Sea Emperor Leviathan and the five remaining Sea Emperor Leviathan Eggs. The Aquarium is teeming with life; schools of fish, coral, grasses, and Flora being scattered all around, some parts of the Aquarium resemble the Grand Reef. There are also small cave systems, one containing a pair of Oculus, the only place they are found other than the Jellyshroom Caves. Large pillars made from the same material as Alien Bases can be found running in two lines, parallel to each other in the middle of the Aquarium, topped with larger, green, rectangular lights. Aggressive creatures, such as Stalkers, Bonesharks, and Cave Crawlers, will be passive to the player and are thus not a threat. Players can safely ride their Seamoth around the aquarium regardless of the depth limit. Two Ion Cubes can be found here, one on a pedestal near the Arch at the back of the Aquarium, and another located in a cavern system having seemingly been abandoned during the evacuation of Precursors.

Pipe System


Pipe System

Eight Alien Vent Entrance Points are located in the aquarium, which pumps oxygen-rich water into the aquarium to keep a stable environment. Peepers use these vents to travel to and from the surface carrying Enzyme 42.

Incubator Device


Incubator Device

The Incubator Device is found in a large hollow in the ground surrounded by small mounds of rock amongst which the Emperor will nestle itself when the player gets close to the 5 eggs that are on it. There is an Arch directly behind the Incubator, which connects to an Arch near the Quarantine Enforcement Platform. The eggs can be hatched using Hatching Enzymes.

Data Bank Entries

This device appears to be the origin of the raw mineral that forms the base of the ion cubes which power smaller alien systems. Likely drawing power itself from the main thermal plant, this device may represent an almost limitless source of energy.

According to translated data logs, an indigenous leviathan species was found to produce a unique substance referred to as 'Enzyme 42', which inhibited the symptoms of the kharaa bacterial infection in other indigenous organisms. The specimen was captured and contained in a purpose-built habitat for further study.

The alien researchers went to great lengths to provide for the lifeform's environmental needs, including the import of interdependent flora and fauna via an onsite warpgate, however its health quickly deteriorated.

When quarantine was imposed all warp gates and forcefields were sealed. All attempts to develop the enzyme into a vaccine had been unsuccessful.

Shell Composition:
The shell casing is formed from thick layers of carbon-composite, suggesting an extensive gestation period. This leviathan species may give birth just once per century, perhaps just once in their lifetimes.

Shell Casing Incisions:
Precise incisions suggest a laser-based tool was used to cut open the egg casing and forcibly remove the fetus inside, prior to full gestation.

- Time-pressure to develop a bacterial vaccine may have driven the alien researchers to cut open this egg and remove the fetus for study
- It is also possible that, removed from its parent and natural habitat, some vital condition for the infant to hatch naturally was not met


Found preserved in a display case, it was likely a child of the adult specimen contained within the facility.

- Superficial damage to the specimen indicates it was artificially removed from its egg-casing
- Stunted tissue development suggests the organism expired during the removal process
- Tissue samples have been taken from the digestive tract

- It appears the aliens were attempting to formulate a cure for the bacterium from enzymes produced in this specimen's digestive system
- Without a young, healthy specimen these efforts were in vain

Water flowing to and from the primary containment facility is being automatically controlled, independently of other safeguards. Data on the water composition has been recorded:

Water is being drawn from different biomes around the surface of the planet. The water temperature is considerably lower than the volcanic environment outside the facility, while micro-organism and nutrient counts are substantially higher.

Oxygen-deprived water is being flooded from the system and recycled back to the surface.


The pipes drawing water into the containment facility are filled with peepers arriving from the surface.

- The fish show no signs of distress
- The specimens scanned have all consumed high quantities of seeds and organic matter from the surface
- Some specimens are beginning to show signs of infection


A peeper specimen was observed emitting a faint, fluorescent enzyme trail, and engaging in unusual behavioral patterns.

- Peeper is actively approaching other creatures, including predators
- The specimen is host to a bacterial infection, however the infection is currently dormant
- Peeper's stomach cavity contains an unknown enzyme of foreign origin

Chemical Analysis of Enzyme:
- Bears some superficial similarity to the stomach enzymes of larger predators
- Contact with the enzyme appears to inhibit the symptoms of the bacterial infection
- Complex structure renders synthesis impossible

Assessment: Recommend further research into enzyme origin

Scans indicate this arch was left inactive when the facility was abandoned. It likely served as an access point to the surface of the planet. It is much too small for the emperor to pass through, but would accommodate smaller lifeforms.

An access point to the alien piping system transporting water to and from the containment facility. Peepers are using the pipe network to travel to and from the surface.


While all other creatures encountered within the facility are isolated within it, peepers appear to be coming and going of their own accord via the alien pipe network.

- On arrival, peepers are approaching the sea emperor
- Peepers exhibit a natural affinity for the stomach enzymes being expelled by the emperor
- Peepers which have come into contact with the enzyme are returning to the pipe network

- This behavior must be the source of Enzyme 42 on 4546B, or the area thereof which supports life
- It is likely also responsible for the survival of the emperor and the other lifeforms contained within the facility



1. Feeding & Digestion
Alien research data indicates that despite its size this species feeds entirely on microorganisms it filters from the water, which themselves depend on a complicated ecosystem of plant and animal life.

2. Reproduction
Large, ovary-like organs are carried in the creature's middle section, suggesting that like other species on this planet it produces eggs, however internal scar tissue indicates probable infertility.

3. Enzyme 42
The emperor manufactures Enzyme 42 within its stomach cavity to break down its food, and will occasionally expel it into the surrounding waters. This substance was found to neutralize the effects of the bacterium, and its presence in the ecosystem today would explain how life on the planet survived the outbreak. It would remain to be explained by what mechanism the enzyme is being delivered.

4. Health
Comparative analysis of size and metabolic rates indicates the specimen captured by the researchers was approximately 1,600 years old. Extensive internal and external scar tissue suggest it had lived well in excess of the peak lifespan for its species.

Assessment: While a healthy emperor specimen may have held some potential as a cure, it is unlikely any research subjects survived quarantine procedures.


1. (Shell)
Uncommonly strong shell lining. Organic growth on the exterior suggests these eggs may be hundreds or thousands of years old.

2. (Alien Tubes)
Alien devices penetrate the outer shell layer. Likely designed to supply them with nutrients, and to isolate them from the surrounding environment.

3. (Amniotic Sack)
Like many eggs on 4546B, these do not contain a nutrient supply which is slowly exhausted by the embryo. Instead they exist in a form of natural stasis, awaiting appropriate hatching conditions.

4. (Fetal Organism)
There is a high genetic match between these organisms and the leviathan in the vicinity. They appear to be stable and healthy.

It is likely that ideal hatching conditions for the eggs vary considerably from ideal survival conditions for the parent.


The emperor specimen's eggs are attached to some form of incubator.

In a normal life cycle it seems likely that sea emperors would have buried their eggs in shallower waters, where different organic materials in the soil would have triggered a hatching response. The incubator suggests the aliens had resorted to developing artificial hatching enzymes which would simulate the eggs' natural hatching environment, but were unable to discover the formula.

With extensive information on the sea emperors themselves it may still be possible to fabricate an artificial hatching enzyme using indigenous ingredients, however the only surviving source of that information may be the sea emperor itself.


Main article: Achievements
Spoiler alert: The following section contains story related material.
PCFAchievement Fourteen Thousand Leagues Under the Sea

Find the Primary Containment Facility

How to obtain: The player must find and enter the Primary Containment Facility in the Lava Lakes.



  • The previous name for the Primary Containment Facility was the Primary Research Facility.
  • The concept art for The Sea Emperor Leviathan's aquarium features a unknown squid in the bottom right hand corner, possibly a earlier version of the Shuttle Bug but has the colour scheme resembling the Sea Monkey in Subnautica Below Zero.
  • Scanning creatures within the aquarium will result in the scanner screen displaying them as "Normal", or free from infection.
  • It isn't recommended to bring the Prawn Suit into the aquarium without a Jump Jet Upgrade, as the bottom is too far from the platform, and getting out of the moonpool may prove to be a challenge. With a jump jet upgrade equipped, a Prawn Suit can be piloted into the depths of the aquarium and launch all the way out without the need for a Grappling Arm.