Quick comparison
| Stat | Seamoth | PRAWN Suit |
|---|---|---|
| Build cost | ~700 titanium | ~2,400 titanium + plasteel + lithium |
| Top speed | 11 m/s | 5 m/s (walking), 9 m/s (boost) |
| Default depth | 200 m | 900 m |
| Max depth (with module) | 900 m | 1,500 m |
| HP | 300 | 600 |
| Armament | None by default | Drill arm, grappling arm, torpedo arm |
| Power cell slots | 2 (4 with module) | 2 (fixed) |
| Storage | 8-slot locker | None by default |
| Crafting | Mobile vehicle bay (no) | Fabricator-compatible |
When the Seamoth wins
The Seamoth is the better choice for exploration, early-game resource runs, and any trip where speed matters more than durability. It is also far cheaper — a fraction of the PRAWN's titanium cost — and the depth module upgrade path is simpler.
The Seamoth also has a unique advantage: it is the only vehicle that can be parked indefinitely. PRAWN Suits require recharging on a Moonpool after every 20 minutes of use; the Seamoth can be left anywhere and re-entered at will.
When the PRAWN wins
The PRAWN is mandatory for three things: deep lava zones (the thermal reactor is the only way to survive the heat), large resource outcropping mining (the drill arm one-shots every outcropping in the game), and leviathan-class combat (the PRAWN's 600 HP and drill combo can take down a Reaper if you are skilled). It is also the only vehicle that can grapple and jump, which opens traversal routes the Seamoth cannot take.
Cost vs. benefit
The Seamoth is roughly one-third the cost of the PRAWN. If you are early-game, the cost difference alone is enough to recommend Seamoth first. By the time you have the resources for the PRAWN, you should already have a fully-upgraded Seamoth, and that is the right progression order.
Late-game lava zones
The Inactive Lava Zone and the Lava Castle are the test. The Seamoth takes 1 HP of heat damage per second at lava depth, and the player inside takes 1 HP per second from the same. The PRAWN's thermal reactor eliminates this entirely, and the PRAWN's drill is the only tool that can break through the lava-zone sulfur outcroppings. If you go to the lava zone in a Seamoth, you will die in under 5 minutes.
What about the Cyclops?
The Cyclops is the third vehicle, but it is a mobile base rather than a personal vehicle. It cannot enter the lava zones — the same heat rules apply. The Cyclops is best used as a mobile scanner room and a launch point for PRAWN dives. Most players build the Seamoth first, the PRAWN second, and the Cyclops third, in that order.
Common build order
- Seamoth (depth module + sonar + storage).
- PRAWN (drill arm + grappling arm + thermal reactor).
- Cyclops (sonar + engine efficiency module + storage).
When you should skip the Seamoth
There is one case where skipping the Seamoth is correct: if you find a PRAWN fragment very early (within the first 30 minutes) and you already have a Moonpool. In that case, building the PRAWN first is fine — the PRAWN can do everything the Seamoth can do, just slower. But for the typical player, the Seamoth is still the recommended first vehicle.