Understanding Lost River
An interconnected deep cave ecosystem with brine pools, fossils and alien-story routes.
This is an original reference for the first Subnautica. Your current depth rating, oxygen, available tools and navigation route determine when an objective is practical. Follow actual in-game PDA and Fabricator information for any values that vary by version.
How to use this information
Map one entrance thoroughly, then progress between safe landmarks and prepare for a lower depth limit.
What to avoid
Certain brine areas are hazardous to an unprotected diver; do not assume every pool can be swum through.