Barotrauma Walkthrough — Start to Endgame

Barotrauma is a co-op submarine simulator set in Jupiter's moon Europa's subsurface ocean. Your crew operates a submarine through procedurally generated cave systems filled with hostile alien creatures, completing missions between outposts. Every crew member has a specific role: Captain navigates, Engineer manages the reactor, Medic handles injuries, Security fights boarders, and Mechanic repairs hull breaches. The game shines in multiplayer chaos — someone accidentally floods a compartment, a creature breaches the hull, the reactor goes critical, and the Medic is administering the wrong drug — all simultaneously. Friendly fire and crew sabotage add human drama to the alien horror.

This walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. Follow this path to avoid common traps that stall most players.

Quick Progression Summary

Phase 1: Getting Started — Europa

Jupiter's moon with a subsurface ocean. The entire game takes place in Europa's underwater cave systems between outposts. Depth determines difficulty — shallow areas near outposts are safer, deep areas face extreme pressure and dangerous creatures.

Level/Difficulty: All depths Key Rewards: Campaign progression, creature encounters, resource collection

What to Do in Europa

1. Learn submarine management. The submarine has interconnected systems: reactor (power), engines (movement), pumps (water removal), weapons (turrets), and life support (oxygen). Spend your first session getting comfortable with this.
2. Pick Engineer as your starting build. It's the most forgiving option.
3. The reactor is the most important system. If it overloads, the sub explodes. Keep reactor output at or slightly above current power demand. Never leave it unattended during combat.
4. Acquire your first equipment upgrade — SMG or whatever's available.
5. Clear all main content before moving on.

Phase 1 Checklist

• Understand submarine management fundamentals
• Engineer selected and functional
• Europa main content cleared
• Ready for Submarine Interior

Phase 2: Early Game — Submarine Interior

Your home and workplace. The submarine's compartments include: Command (bridge), Engineering (reactor), Medical Bay, Armory, Storage, and Crew Quarters. Learning the submarine layout is essential for emergency response.

Level/Difficulty: All missions Key Rewards: Systems access, crafting stations, storage, survival

What to Do in Submarine Interior

1. Work on crew roles. Each role has unique talents and responsibilities. This system becomes critical from here on.
2. Farm for SMG if you haven't already. It's the key upgrade for this phase.
3. Fabricate bandages, morphine, and antibiotics before every mission. Running out of medical supplies mid-mission while someone is bleeding out is a crew-ending mistake.
4. Complete all objectives before pushing to Ruins.
5. Consider whether Captain might suit your playstyle better than Engineer.

Phase 2 Checklist

• crew roles integrated into gameplay
• SMG acquired
• Submarine Interior fully cleared
• Ready for Ruins

Phase 3: Mid Game — Ruins

Ancient alien structures scattered throughout Europa's caves. Ruins contain valuable artifacts, alien technology, and dangerous guardians. Exploring ruins requires diving suits and combat readiness. The loot from ruins is the most valuable in the game.

Level/Difficulty: Mid-late campaign Key Rewards: Alien artifacts, rare materials, unique equipment, highest value loot

What to Do in Ruins

1. Master crafting. Fabricators aboard the sub create weapons, medical supplies, tools, and equipment from raw materials. This unlocks a new layer of gameplay.
2. Start working toward Revolver. It's the best equipment and becomes accessible around now.
3. Water flooding spreads through connected compartments via doors. Close bulkhead doors during breaches to contain flooding. Pumps remove water but consume significant battery power.
4. This area is the main skill check. If you can clear it, you're ready for late game.
5. Start investing in underwater creatures for the tactical depth you'll need going forward.

Phase 3 Checklist

• crafting mastered
• Revolver acquired or in progress
• Ruins fully cleared
• Ready for Abyss

Phase 4: Late Game — Abyss

The deepest areas of Europa's ocean with extreme pressure, near-zero visibility, and the largest creatures. Abyss missions are the most dangerous and rewarding. Only well-equipped submarines with experienced crews should attempt Abyss missions.

Level/Difficulty: Late campaign Key Rewards: Rare resources, endgame content, Endworm encounters

What to Do in Abyss

1. Finalize your build. You should be running Captain or Engineer with optimized gear.
2. Revolver should be your primary. If you don't have it yet, prioritize getting it.
3. Wiring connects every electrical system. Learn basic wiring to fix broken connections during emergencies. A severed wire between the reactor and engines leaves you dead in the water.
4. mission system optimization starts here. Small improvements compound into massive advantages.
5. Farm this area for the resources needed to push into Outpost.

Phase 4 Checklist

• Build fully optimized
• Revolver upgraded to max
• Abyss fully cleared
• Ready for Outpost

Phase 5: Endgame — Outpost

Settlements between missions where you buy supplies, hire crew, repair the submarine, and take new missions. Outpost shops sell weapons, medical supplies, materials, and submarine upgrades. Spending wisely at outposts determines mission preparedness.

Level/Difficulty: Between missions Key Rewards: Resupply, crew hiring, submarine repairs, mission selection

What to Do in Outpost

1. Outpost tests everything. Come prepared with your best build and gear.
2. Diving suits protect against water pressure outside the sub. Never go outside without a diving suit — pressure kills in seconds. Carry a welding tool for exterior hull repairs.
3. The endgame loop: run Outpost, optimize gear, push harder content.
4. Experiment with Mechanic for a fresh take once you've mastered the standard builds.
5. This is where mission system mastery separates good players from great ones.

Phase 5 Checklist

• Endgame content on farm
• Best-in-slot gear acquired
• Outpost fully cleared
• Ready for challenge content

Common Progression Mistakes

• Leaving the reactor unattended — reactor overloads without constant management, and a meltdown kills the entire crew.
• Not closing bulkhead doors during flooding — water spreads through every open door, sinking the entire sub instead of just one compartment.
• Administering wrong drugs as Medic — overdosing a crew member with morphine puts them in a coma. Learn drug interactions from the medical guide.
• Going outside without a diving suit — the pressure instantly kills unprotected crew. Always check suit integrity before exiting.
• Ignoring small hull breaches — tiny leaks compound over time. A small breach becomes a flooding emergency if not welded immediately.

Key Tips for Smooth Progression

1. The reactor is the most important system. If it overloads, the sub explodes. Keep reactor output at or slightly above current power demand. Never leave it unattended during combat.
2. Fabricate bandages, morphine, and antibiotics before every mission. Running out of medical supplies mid-mission while someone is bleeding out is a crew-ending mistake.
3. Water flooding spreads through connected compartments via doors. Close bulkhead doors during breaches to contain flooding. Pumps remove water but consume significant battery power.
4. Wiring connects every electrical system. Learn basic wiring to fix broken connections during emergencies. A severed wire between the reactor and engines leaves you dead in the water.
5. Diving suits protect against water pressure outside the sub. Never go outside without a diving suit — pressure kills in seconds. Carry a welding tool for exterior hull repairs.

For detailed build optimization, see Barotrauma builds. For quick wins, check tips & tricks.