Why Does the Tadpole or Moonpool Say There Is Not Enough Space?

Short answer

If Subnautica 2 says your Tadpole, Moonpool, Tadpole Dock, or Vehicle Fabricator does not have enough space, test the Moonpool in open water first. Build a clean powered room, attach one Tadpole Dock, keep the underside clear of terrain, rocks, ruins, foundations, and other base pieces, then try docking from below.

If that works, your old base layout is blocked or too cramped. If it still fails, you may be hitting an Early Access docking bug. Either way, think in volumes, not just floor tiles: the Tadpole needs room inside the Moonpool, below it, around the dock attachment, and around the chassis you are using.

Update to Hotfix 2 first

Early Access Hotfix 2 is important because it fixed several Tadpole-adjacent problems:

• Hammerheads should no longer be as attracted to Tadpole lights.
• A bug where players could be teleported back to base while exploring in a Tadpole was fixed.
• An infinite oxygen bug after dying while piloting a Tadpole was fixed.
• A crash when losing connection from a multiplayer game was fixed.
• Epic visual settings performance was improved.

Update to Hotfix 2 before testing your Moonpool. The official notes do not claim to solve every insufficient-space message, phantom obstruction, Haul Chassis clearance issue, or multi-dock base layout, so a failed layout still needs a clean open-water test.

The likely causes, from most to least common

1. The Moonpool room is too small for the dock or chassis

Community reports repeatedly point to players making a Moonpool that looks large enough, then discovering that the Tadpole Dock or Vehicle Fabricator needs more room than expected. The Haul Chassis seems especially sensitive because it increases the effective vehicle size.

If a standard or compact Moonpool fails, expand the room itself, not only the water opening. Give the dock side extra length and avoid placing the dock hard against a wall or crowded corner.

2. There is not enough vertical clearance below the Moonpool

This is easy to miss. The Moonpool may look open from above, but the Tadpole needs space below the base to approach, align, and dock. Terrain, ruins, foundation pieces, rocks, or base modules below the Moonpool can block the docking volume.

If you built close to the seafloor, over ruins, or beside uneven terrain, try a higher test build in open water before assuming the save is broken.

3. The dock, fabricator, or vehicle is obstructing itself

Several community threads describe cases where the Tadpole, a second dock, a second Moonpool, the Vehicle Fabricator, or another base part appears to interfere with docking. Because this is Early Access, it is not always obvious whether the obstruction is intended collision or a bug.

Before tearing down the whole room, move nearby pieces away from the dock side and test with one dock, one Moonpool, and one Tadpole.

4. The base has power or module-state problems

If the Moonpool is built correctly but nothing behaves, check base power and whether the Tadpole Dock is actually attached to the Moonpool. Power issues can look like interaction issues, especially in a new base where multiple systems are being added at once.

5. The Tadpole is not aligned with the correct docking approach

Approach from below and give yourself space to line up cleanly. Do not use a tight cave ceiling, crowded base underside, or terrain slope as your test case. The first successful dock is easier to get in clear water than in a scenic but cramped base location.

6. It may be a real Early Access bug

Some reports describe phantom colliders, docking stations becoming unusable after adding extra Moonpool pieces, and insufficient-space errors that do not match the visible layout. Those should be treated as possible bugs. If a clean test build works but your main base does not, the base layout may have a hidden obstruction or bugged state.

A safe troubleshooting sequence

Use this order before rebuilding a whole base:

1. Confirm everyone is on Hotfix 2 or later. This matters for Tadpole teleport, Hammerhead attraction, and multiplayer crash behavior.
2. Save before major rebuilding. Do not experiment destructively without a rollback point.
3. Build a test Moonpool in open water. Use a simple powered base section away from terrain.
4. Attach only one Tadpole Dock. Keep the test layout boring until docking works.
5. Add extra room length and height. If the smallest room fails, expand the room before adding decorations or extra systems.
6. Test with the basic Tadpole setup first. Then test the chassis or attachment that caused trouble.
7. Move the vehicle out of the construction volume. Do not park the Tadpole near the place where the dock or fabricator is being built.
8. Restart the game if the layout should work but still fails. Community reports suggest some states clear only after a restart, although this is not an official universal fix.
9. Only then rebuild the main base. If the open-water test works, copy that spacing back to your real base location.

What changed with Hammerheads and Tadpole lights

Hotfix 2 specifically says Hammerheads are no longer as attracted to Tadpole lights. Before the fix, the official note says this could result in Hammerheads following players back to bases and hanging around trying to reach the Tadpole.

That means a Hammerhead near your base after Hotfix 2 should be interpreted carefully:

• If your platform has not received Hotfix 2 yet, you may still be seeing older behavior.
• If the Hammerhead is near your vehicle but not obsessively following lights home, the fix may be working but the area may still be dangerous.
• If Hammerheads still camp a docked Tadpole in the current build, it is worth reporting with patch version, location, lights on/off, and whether the vehicle was docked.

What not to conclude too quickly

Do not assume every insufficient-space error is a bug. Many cases are likely real clearance problems that the UI explains poorly. At the same time, do not assume every community workaround is a rule. A 6x6 layout, a longer room, a higher foundation, or a restart may solve one player’s base and fail another if terrain, chassis, dock placement, or extra modules differ.

The best current advice is to build a boring test Moonpool in open water, learn the minimum spacing for your chassis, then rebuild your real base with more margin than you think you need.

Sources and further reading

• Unknown Worlds: Subnautica 2 Early Access Hotfix 2
• Reddit: How is this not enough space?
• Reddit: Haul Tadpole insufficient space
• Reddit: Moonpool phantom collider
• Reddit: Moonpool and Tadpole Dock is glitched
• Steam: Feedback after first playthrough of Early Access
• Shacknews: Insufficient space to dock guide

Version notes

Checked on May 23, 2026 against Early Access Hotfix 2 and a sample of recent Reddit, Steam, and guide-page discussion. This FAQ uses community reports to identify common failure patterns, but it still needs hands-on current-build verification for exact Moonpool dimensions by chassis.