Submarine-only labyrinth monument with a green/blue/red puzzle ladder, scientist patrols and elite-tier loot inside the deepest sealed rooms.
| Tier | Red (highest underwater) |
|---|---|
| Access | Submarine only — locate via Cargo Ship or random ocean tiles |
| Puzzle | Green card → Blue card → Red card progression |
| Scientists | 4-8 inside, hazmat-equipped |
| Loot | Elite Crates, Scientist Crates, Component bins, occasional Locked Crate |
| Radiation | Mild (most rooms); Hazmat suit recommended |
Underwater Labs are Rust submarine-only monuments — sprawling labyrinths of sealed rooms accessible only by submarine, gated by puzzles and patrolled by hazmat-equipped scientists. They are the only practical source of consistent red-card loot for solos and small groups who cannot credibly clear Launch Site. If you have a submarine, two cards and twenty minutes, an Underwater Lab run is one of the best loot-per-effort grinds in Rust.
Underwater Labs are the highest-tier loot pool you can hit without contesting Launch Site. Inside the sealed rooms expect:
Total per-run yield is comparable to a green/blue puzzle monument cleared on land, but the elite tier rolls are noticeably better.
Inside the labs you face 4-8 scientists per dive depending on lab size, all wearing hazmat suits and carrying SARs or MP5s. They patrol the corridors and do not sleep — every room is hostile until cleared. Mild radiation in some areas means a Hazmat Suit is standard kit.
The puzzle progression is Green → Blue → Red, identical to land monuments. Bring a keycard set before diving — there is no card spawner inside reliably.
Above water: the area around an Underwater Lab is open ocean. Hostile players in submarines or boats are a real risk. Park your submarine somewhere unobvious before diving.
Solo loadout: SAR or M39 + Python sidearm, Roadsign + Coffee Can armour, Hazmat suit (carry it; switch when needed), 2 large medkits, blue and red cards, 200 5.56 ammo.
Duo/trio: one player with a Pump Shotgun for tight corridors, one with an AK47 for distance, plus the keycard runner.
Tea: Pure Max Health Tea before diving — corridor fights are HP-attrition battles where the +20 HP buffer matters.
Mistake to avoid: diving without checking the surface for hostile players. Submarines are slow and obvious. Run a 30-second perimeter check before committing.