Unlocking the Tadpole Pens in Subnautica 2 requires a specific access code, but don’t expect to find it lying around the ruins themselves. The item is stashed in a completely different area, so save your time and bypass the site initially. Your journey will take you into treacherous, high-temperature submerged caverns—keep a sharp eye on your vitals, particularly oxygen and hydration, during the descent.
Below, we break down exactly how to locate the security keycode required to access the Tadpole Pens.
[Editor’s Note: Before embarking on this trek, open your character menu and activate all landmark signals. This adjustment is essential for quickly identifying the waypoints referenced in this guide.]Investigating the Tadpole Pens
Once you have secured the Wander Blackbox and successfully treated the Angel Comb, you will trigger a Noetic Advisor notification labeled “Tadpole Pens.” Acknowledge this alert to officially log the mission. Before setting out, pack supplies: bring sufficient sustenance, hydration, diversion flares, a fully charged scanner, and an air bladder. This expedition reaches significant depths, making the air bladder’s emergency oxygen burst an absolute necessity for survival. While a standard air tank is mandatory, you do not need advanced life support or a submersible for this objective.
Set your course from the Lifepod and swim 690 meters east. There is no need for a deep dive until you arrive directly over the beacon. While you will eventually spot the Tadpole Pens structure in the distance, focus your approach on the oxygen tunic—the small, blue, bubble-releasing flora situated in the gorge directly across from the facility’s entrance.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
Interact with the bubbles to top off your supply, then swim into the facility and turn left to activate the red button within the corridor.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
The security door will remain sealed without the proper access key. Retreat to the exterior oxygen tunic to replenish your reserves before heading to the next location.
Retrieving the Access Key
While you might be tempted to scavenge the Tadpole Pens, the code is not among the local loot. Shortly after pressing the red button, a follow-up Noetic Advisor alert will ping, marking the location of the Zip Blackbox. Interacting with this device grants you the clearance required.
While it is standard practice to return to your Lifepod to sync with the Noetic Advisor, you can proceed directly toward the signal coordinates if you prefer to avoid the backtracking.
From the Tadpole Pens: Swim 210 meters southwest. Utilize the various oxygen tunics along the route to maintain your levels. Look for a circular alien artifact perched on the cliff edge; dive beneath it and navigate through the wide gap on the left (adjacent to the volcanic mound and jellyfish ring). Follow the tunnel southwest into a cavern anchored by a prominent, glowing coral formation.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
From the Lifepod: Head 350 meters southeast, navigating past Chap’s Blackbox. Descend at the cliff edge, recharge at the nearby oxygen tunic, and enter the large cavernous opening located beside it. You may explore the Hot Cave Basement before proceeding.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
Continue north-northeast and take the first tunnel on your right to arrive in the cavern containing the fiery coral.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
Regardless of your chosen path, top off your air at the oxygen tunic on the north-northeast side of this chamber. Locate the adjacent cave opening and descend to the floor to discover Zip’s Blackbox resting on a large purple root. Accessing it will provide you with the Kurul-level access key.
Graphic: Marloes Valentina Stella/Polygon | Source images: Unknown Worlds Entertainment/Krafton via Polygon
Return to the Tadpole Pens and activate the red button once more to conclude the mission. You will find a pressurized, breathable area and a Noetic Advisor terminal waiting beyond the previously locked gate.
Source: Polygon
