Subnautica 2 Guide: How to Find the Tadpole Pens Keycode

Getting locked out of an underwater base while you slowly run out of air is a miserable way to end your expedition.

You just swam nearly 700 meters east of your Lifepod, dodged a bunch of lava vents, and finally reached the Tadpole Pens. You hit the red button in the corridor, and nothing happens. The door needs a keycode. If you start swimming around the immediate facility looking for a datapad, you will absolutely drown. A colonist named Zip took the code deep into the Hot Caves, and you have to go fetch his blackbox to get inside.

Prepping for the Hot Caves

Before you blindly dive into a magma vent, you need to check your loadout. The path to the keycode is incredibly hostile.

First, you need the Heat Tolerance adaptation. If you try to swim through the lava pipes without clearing the Angel Comb near Wander's blackbox first, the water will literally boil you to death.

Second, you really should bring a Tadpole vehicle. The keycode is sitting at a depth of 310 meters. Your baseline oxygen tank will not survive a round trip of that length without some serious help. Keep a few Air Bladders in your quick slots just in case things go wrong, and utilize the oxygen tunics (the small blue plants emitting bubbles) scattered around the gorge to top off your lungs.

Locating Zip's Blackbox

If you want to waste time, you can swim all the way back to your Lifepod to listen to NOA, which will eventually drop a waypoint for Zip's blackbox. I prefer to skip the commute and just grab the code immediately.

Here is the exact route I use to navigate the cavern system without getting lost in the dark.

Navigation Step	Direction & Details
1. The Descent	Start at the Tadpole Pens and head South/Southwest for about 210 meters. Look for a circular alien device near a cliff edge and swim down into the cavern hole.
2. The Lava Chamber	Follow the glowing blue tunnel southwest until you hit a massive room with a fiery coral vent right in the center.
3. Park the Tadpole	Look for a small cave opening on the right side of the vent chamber (North-Northeast). Exit your Tadpole here. The cave drops past your 250m crush limit.
4. Grab the Code	Swim down the final tunnel by hand to a depth of 310 meters. Zip's Blackbox is sitting on a large purple root. Interact with it to get the "kurul level access key".

Unlocking the Tadpole Pens

Once you grab the kurul access key from the supply crate, swimming back up to your parked vehicle is a race against the clock. Hit your Air Bladder if your vision starts to fade.

Pilot your vehicle back to the main Tadpole Pens structure. You can finally push that red button in the corridor, and the heavy door will slide open. You don't have to worry about oxygen inside the facility because the room provides breathable air. Take a second to scan the broken Repair Tool sitting inside if you haven't unlocked that blueprint yet. Climb the ladder in the back of the room to reach a NOA terminal. Exhausting the dialogue options here gives you your next major story waypoint.

Still struggling to survive on Proteus? Check out my complete Subnautica 2 Guide Hub for base building tips, resource maps, and more.