The short answer
Get Heat Tolerance before travelling to the Tadpole Pens. The door code is recovered from Zip’s black box in the Hot Caves.
Before you start
- Heat Tolerance, improved oxygen and charged tools.
- Bring food, water and healing; this is a longer trip than the early black boxes.
Prepare for NOA’s objective
The Pens signal is roughly 675 m east of the Lifepod. The published walkthrough received it after the other early black boxes. Follow the objective in your save rather than assuming an exact timer.
Sources for this section
Reach the code
- From the Pens, head south at about 195° through the ravine beneath the lava pipes.
- Enter the ground-level cave and take the glowing blue tunnel southwest.
- In the chamber with the central lava vent, descend toward the small opening on its right.
- Leave the Tadpole before exceeding its depth rating; swim the final section only with sufficient oxygen.
- Find the human hologram above the purple growth and recover Zip’s black box. Return to unlock the Pens.
Sources for this section
Your checklist
0 of 3 ready · Stored only while this page is open.
Research checked 2026-09-12. This is a source-based guide; Kingy has not independently play-tested these steps. Evidence and coverage.