Subnautica 2: Tadpole Pens keycode
Overview & Key Takeaways
Throughout Subnautica 2, your ever-present AI companion, NoA, will dripfeed you a series of signals to follow, to piece together the mystery of what happened here on Proteus. It won't be long before you're given the quest to "Investigate Tadpole Pens", taking you further to the east than ever before - and into some ragingly high temperatures while you're at it.
As you may have discovered, however, just reaching the Tadpole Pens isn't enough. Inside you'll find a locked door which won't open until you have the correct "keycode". This keycode can be found inside the Hot Cave below Tailings Village, not far at all from your current positino. In this quick guide, I'll show you exactly where to go to get the Tadpole Pens keycode in Subnautica 2, and how to use it to Investigate the Tadpole Pens themselves.
Throughout Subnautica 2, your ever-present AI companion, NoA, will dripfeed you a series of signals to follow, to piece together the mystery of what happened here on Proteus. It won't be long before you're given the quest to "Investigate Tadpole Pens", taking you further to the east than ever before - and into some ragingly high temperatures while you're at it.
As you may have discovered, however, just reaching the Tadpole Pens isn't enough. Inside you'll find a locked door which won't open until you have the correct "keycode". This keycode can be found inside the Hot Cave below Tailings Village, not far at all from your current positino. In this quick guide, I'll show you exactly where to go to get the Tadpole Pens keycode in Subnautica 2, and how to use it to Investigate the Tadpole Pens themselves.
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How to Investigate Tadpole Pens
Image credit: RPS/MapGenie/Unknown Worlds
The Tadpole Pens can be found inside Subnautica 2's hot biome, 680 metres directly east from the Lifepod, at 150m depth. You cannot properly explore the area until you have unlocked the Heat Tolerance Adaptation, which allows you to withstand the extreme temperatures of this biome.
I also highly recommend that you first unlock and build a Tadpole vehicle, because this will make exploring the deeper reaches of the hot biome far easier than diving on your own - even if you have maxed out your Oxygen supply.
Image credit: RPS/Unknown Worlds
As you enter the Tadpole Pens, turn left and head straight to the closed door in front of you. In the corridor is a button which you can press to start an authorization scan. But if you try this, the scan will turn red and your PDA will tell you that there is a "Keycode required".
The NoA terminal which completes this quest is behind that door. So, to investigate the Tadpole Pens, you first need to acquire the Tadpole Pens keycode. Fortunately, the keycode is not at all far from the Tadpole Pens themselves.
How to get the Tadpole Pens keycode
To get the Tadpole Pens keycode, exit the Tadpole Pens and head directly southwest through the canyon. You'll quickly enter Tailings Village - an area dotted with spherical structures.
Image credit: RPS/Unknown Worlds
Image credit: RPS/Unknown Worlds
In the ground there are four large holes leading into the Hot Cave - a massive cave system below. Swim down one of these holes, and head through the entrance to your southwest into the Hot Cave itself.
Rounding the corner, you'll see the cave open up into a massive area with a giant thermal vent in the centre. Swim down to the right-hand side of the thermal vent, and you'll see a hole in the rock leading further down.
Image credit: RPS/Unknown Worlds
Image credit: RPS/Unknown Worlds
Swim through the hole and down as low as you can go. You'll see a massive purple Titan Rockbore root at the very bottom of the cave. On top of this root, you'll find Zip's Blackbox. Interact with the Blackbox to obtain the Tadpole Pens keycode. It's called the "Kurul Level Access Code" in your Databank, but that's exactly what you need to investigate the Tadpole Pens.
Image credit: RPS/Unknown Worlds
Image credit: RPS/Unknown Worlds
Opening the Tadpole Pens door
Now that you've got the keycode, retrace your steps back out of the Hot Cave and head back to the northeast to enter the Tadpole Pens once more.
Once inside, you can head to that same door to your left and press the button to initialise the scan. This time, the light will turn green, and the door will open. You can look around the room for several objects to scan (including a number of Azum Jars of various sizes). Once you're ready, head up the ladder in this room, and you'll find the NoA Terminal.
Interact with the NoA Terminal and boot it up. I won't spoil the story here, but what follows is a very interesting conversation, dripping with lore. Exhaust all the dialogue to complete the "Investigate Tadpole Pens" quest at last.
That concludes this walkthrough of the Tadpole Pens quest in Subnautica 2, and how to find that pesky missing keycode. If you're still exploring the hot biome, you should know that it's a fantastic source of both Gold and Lithium. But if you're struggling to find other resources for your base back home, check out our guides on where to find Silver and Lead while you're here!
