How we rank base locations
We score each location on four criteria: defensibility (how often you will be attacked while inside), resource proximity (how many useful resources are within a 200 m swim), access to the surface (for emergencies and Seamoth docking), and biomes-within-reach (how many other biomes are within a 5-minute swim). A score out of 10 is listed for each location.
Tier 1: Safe Shallows (0–100 m)
Best for your first base. No leviathans, no aggressive fauna, surface access in 30 seconds.
| Location | Depth | Score | Why |
|---|---|---|---|
| Kelp Forest border (north) | 60 m | 9/10 | Sand, titanium, copper, lead, kelp, peeper, bladderfish all within 200 m. Surface in 40 s. |
| Safe Shallows central plateau | 30 m | 8/10 | Best surface access, but farther from Kelp Forest resources. Good starter base. |
| Grassy Plateaus east shelf | 100 m | 8/10 | Closer to the Mushroom Forest, but the descent takes 90 s. |
Tier 2: Kelp / Mushroom (100–300 m)
Best for your mid-game base. The Mushroom Forest and Deep Kelp are the resource hubs.
| Location | Depth | Score | Why |
|---|---|---|---|
| Mushroom Forest central | 180 m | 9/10 | Acid mushrooms, deep shrooms, gel sacks, lithium — all in walking distance. |
| Kelp Forest south edge | 200 m | 8/10 | Easier surface access than the Mushroom Forest. Stalker threat is the trade-off. |
| Grassy Plateaus south shelf | 140 m | 8/10 | Sand, gold, silver, and a clean view of the Underwater Islands. |
Tier 3: Deep Grand Reef (200–400 m)
The Deep Grand Reef trench is the deepest you can take a Seamoth without modules. Build here once you need to grind deep-zone resources.
| Location | Depth | Score | Why |
|---|---|---|---|
| Trench rim (eastern entrance) | 260 m | 10/10 | Lithium at 1 per 50 m², kyanite within 100 m, easy descent. The top late-game base spot. |
| Trench floor (mid-point) | 350 m | 7/10 | Closer to the Crabsquid cave, but the heat pressure is constant. Only build if you need a deep-water mid-point. |
| Blood Kelp trench (north) | 320 m | 7/10 | Best for blood oil, but Bonesharks spawn at 100% rate here. |
Tier 4: Lost River (400–700 m)
Lost River is the gateway biome. The kyanite and nickel are mandatory, and the Ghost Leviathan spawns make this the most dangerous base location tier.
| Location | Depth | Score | Why |
|---|---|---|---|
| Lost River bone field (west) | 500 m | 8/10 | Highest kyanite density in the game. Ghost Leviathan threat is constant — bring a perimeter sonar. |
| Tree spine corridor | 450 m | 7/10 | Cleaner water, fewer Ghost spawns, but kyanite is sparser. |
Tier 5: Inactive Lava Zone (700–1,400 m)
For your final base. The PRAWN's thermal reactor is required, and the Sea Dragon Leviathan is a constant threat.
| Location | Depth | Score | Why |
|---|---|---|---|
| Lava Zone outskirts (north) | 700 m | 9/10 | Outside the Leviathan's reach (it patrols the inner ring), but close enough for sulfur and lithium farming. |
| Lava Castle chamber (final) | 1,300 m | 6/10 | The deepest base you can build. Only useful for the final boss run. Build it, do the run, abandon it. |
How many bases do you need?
For a typical playthrough, four bases is the right number: Safe Shallows (early), Grassy Plateaus (mid), Deep Grand Reef (late), and Lava Zone outskirts (final). Anything more is overhead. Anything less means long travel times.
Base building tips
- Always build a Moonpool. Without it, the PRAWN's 20-minute charge timer becomes a constant burden.
- Always build a Scanner Room. The resource tracker upgrade is the single biggest time-saver in the game.
- Lockers adjacent to the Moonpool. Otherwise you spend 30 minutes per dive just banking inventory.
- Solar panels for surface bases, thermal reactors for deep bases. Hybrid (solar + thermal) for mid-depth.