Subnautica 2 Tadpole Pens Guide: Find the Keycode

The life pod hums; your hunger meter creeps toward red; there’s a blinking distress signal that refuses to quit. I remember my first trip east—everything felt too far and the water too quiet. You get the keycode and the map changes in a way that makes the hours you spent worth it.

The ocean smells like metal at the life pod before you leave — where the Tadpole Pens sit and why you should care

I’ve chased strange beacons the exact same way you will: methodical, with a little dread. The Tadpole Pens sit roughly 675 metres east of your Life Pod. That distance is long enough to force decisions: carry extra food, water, and a repair kit, or risk turning a quick run into a rescue mission.

You’ll often see the quest appear through a distress signal, but you can also plot a course manually. When you reach the site, watch for an open hatch on the structure’s surface. Entering it leads to a small interior wing where a data entry points straight at the keycode’s origin.

Heads-up: the area is a favored haunt of the Collector Leviathan. Treat its patrols like a timer—move fast and keep cover available.

Where are the Tadpole Pens located?

They’re at the 675 m mark east of the Life Pod. If you prefer landmarks over coordinates, it’s the metal complex with an obvious open hatch and scattered debris that looks like a half-finished pen.

A cave’s warm breath gives itself away — how to find the Zip Blackbox and grab the keycode

When I couldn’t be bothered to swim back to base, I learned a shortcut that saved me half an hour and a tense surface run. The Tadpole Pens keycode is stored on the Zip Blackbox. Two ways to get it:

• Go back to a Life Pod or any NOA Terminal and wait for the Zip Blackbox ping to appear on your console; the signal will mark the blackbox on your map.
• From the Tadpole Pens, head southwest for 200 metres until you find a series of hot caves. Enter and follow the tunnel to a large underground opening. The blackbox sits roughly 250 metres down in that opening.

Bring a Tadpole vehicle for the descent. The active area of the Pens also contains two Tadpole fragments, so you can craft a second Tadpole back at base if you like redundancy. The Zip Blackbox behaves like a heat-seeking needle in the dark, so once you’re in the right cavern the signal snaps into place.

How do I get the Tadpole Pens keycode?

Find the Zip Blackbox. Either wait for its NOA ping at a terminal, or follow the southwest cave route from the Pens, descend ~250 m with a Tadpole, and the blackbox will be there.

The cold metal door won’t budge — how to use the keycode, power the room, and finish the quest

The door near the Pens’ left corridor looks like an afterthought until you stand in front of it and feel stuck. Once you have the Zip Blackbox, return to the Pens and enter the code at the keypad by the locked door on the left side of the structure.

Inside, take the stairs up and power the NOA terminal in the room. Switch the terminal on and speak to Sophie Boucher on the comms to complete the Investigate Tadpole Pens quest. Completing this scene will add the Alien Ruins marker to your map so you can plan your next move toward the story’s next waypoint.

How do I open the locked door in Tadpole Pens?

Enter the keycode from the Zip Blackbox at the keypad, power the NOA terminal upstairs, and speak with Sophie Boucher to trigger the quest completion and map update.

I test these routes using Steam builds and community notes on the Subnautica 2 Discord and Reddit; Unknown Worlds Entertainment’s patch notes are often the definitive source when details shift. If you’re shopping for the game on Steam, it lists Subnautica 2 at about $39.99 (€37) and the community guides there can save hours.

If one path is blocked—use the alternate (NOA ping) method and keep your Tadpole intact. The locked door at the Pens has the feel of a rusted diary that only a code can open. Which route will you try first?