Subnautica 2 Lost River
The bridge biome between mid-game and endgame. Bioluminescent forests, brine pools, and the entry to the Inactive Lava Zone. Five entrances exist; only one fits the Cyclops. <strong>Bring beacons.</strong>
All entrances
Lost River entrance points
Use TeleportPlayer X Y Z in console to jump to coords.
| POI | Biome | Coordinates | Density | Notes |
|---|---|---|---|---|
| Tree Cove (SW Bulb) | Bulb Zone | ~200 m depth | HIGH | ★ Only Cyclops-wide entrance · main access route |
| Mountain Cave | Mountain Island | ~250 m depth | MED | Tight · Seamoth/Prawn only · scenic |
| Blood Kelp Trench | Blood Kelp | ~450 m depth | MED | Crabsquid territory · careful with lights |
| Grand Reef vent | Grand Reef | ~500 m depth | LOW | Tightest entrance · Prawn only · Ghost Leviathan adult patrols |
| Sparse Reef passage | Sparse Reef | ~300 m depth | LOW | Indirect · cave network · long swim |
Quick stats
LOST RIVER — BIOME BRIEF
- Depth band
- 500 – 1,000 m
- Entry depth
- Earliest at 200 m (Bulb Zone)
- Cyclops accessible
- ✓ Tree Cove entrance only
- Major threats
- Ghost Leviathan juvenile · River Prowler
- Resources unique
- Nickel Ore · Magnetite · Uraninite Crystal
- Ambient
- Bioluminescent · brine-pool floor
- Connects to
- Inactive Lava Zone · Lava Castle
Sub-biomes inside
LOST RIVER — SUB-ZONE MAP
- Tree Cove
- Massive bioluminescent tree · entrance hub
- Bone Fields
- Leviathan skeletons · scan for lore
- Ghost Forest
- Brine pool · juvenile Ghost Leviathan
- Cove Tree main hall
- Disease Research Facility (precursor base)
- Junction
- Crossroads to Lava Castle / Inactive Lava Zone
What to harvest
EXCLUSIVE / DENSE RESOURCES
- Nickel Ore
- Required for MK2 depth modules
- Magnetite
- Heavy use in tools and modules
- Uraninite Crystal
- Reactor rod input
- Lithium
- Plasteel — abundant in side caves
- Sulphur (rare)
- Drops from Crashfish only
- Crystalline Sulphur
- Lava Castle floor — scan first
Troubleshooting
- ! I keep getting lost in the Lost River — my Cyclops is stuck.
Cause: The Lost River is a 3D cave system, not a flat zone. Without a Beacon trail you will lose orientation within 5 minutes.
- Drop a Beacon at every junction as you descend. Yellow for "way back to entrance", red for "danger".
- Mark the Tree Cove main hall with a beacon — this is your default rally point.
- Cyclops can't turn easily in tight passages. Reverse out rather than try a U-turn.
- Use Slow + lights off mode — preserve battery; you'll need it for the long climb back.
- ! A juvenile Ghost Leviathan is chasing my Seamoth.
Cause: The Lost River brine zones spawn Ghost Leviathan juveniles at ~30 m length. Slower than Reapers but their grab range is wider.
- Use Perimeter Defense stun the moment the first roar plays.
- Climb out of the brine — they don't patrol upper Lost River.
- Stasis Rifle works the same as on Reapers.
- Solo: avoid the Ghost Forest entirely until you have a Cyclops with MK1+.
- ! How deep can I go without dying to pressure?
Cause: Each vehicle has a hard depth limit. Below it: rapid hull cracking, instant kill at 1.5× depth.
- Seamoth base: 200 m. With MK1+MK2+MK3: 900 m.
- Prawn Suit base: 900 m. With MK1+MK2: 1,300 m.
- Cyclops base: 500 m. With MK1: 900, MK2: 1,300, MK3: 1,700.
- Lost River bottom is ~1,000 m. You need MK2 minimum to explore safely.