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 guide covers everything you need: core mechanics, the best builds, equipment worth investing in, location progression, and the tips that actually make a difference.
Core Mechanics
submarine management
The submarine has interconnected systems: reactor (power), engines (movement), pumps (water removal), weapons (turrets), and life support (oxygen). Damage to any system cascades — losing power stops pumps, flooding shorts electrical systems, and hull breaches let water and creatures in. Managing these systems under pressure is the core challenge.
crew roles
Each role has unique talents and responsibilities. The Captain drives and navigates. Engineers manage the reactor output (too high = meltdown, too low = no power). Medics craft medical supplies and treat injuries. Security officers man turrets and fight boarders. Mechanics repair hull breaches and maintain systems.
crafting
Fabricators aboard the sub create weapons, medical supplies, tools, and equipment from raw materials. Medics craft drugs and bandages. Engineers craft tools and components. Materials are purchased at outposts or looted from wrecks. Crafting between missions prepares you for the next mission's dangers.
underwater creatures
Europa's ocean is full of hostile alien life. Mudraptors board the sub through breaches. Husks infect crew members, turning them against others. Molochs are massive creatures that damage the hull. Endworms are the apex predator — encounters with them are desperate survival situations.
mission system
Missions are taken at outposts with varying objectives: escort, salvage, monster hunting, exploration, and cargo delivery. Difficulty and reward scale with depth — deeper missions face stronger creatures and harsher pressure. The campaign progresses through a series of outpost stops across Europa's ocean.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Captain | S | Stay at the navigation terminal, chart safe routes through cave systems, call out threats on sonar, and coordinate crew during emergencies. | Helm skill, navigation knowledge, leadership |
| Engineer | S | Monitor reactor output constantly, adjust for power demand, repair electrical systems, and prevent meltdowns during combat. | Electrical skill, Mechanical skill, reactor management |
| Medic | S | Craft medical supplies between missions, treat injuries immediately during combat, and manage drug interactions to avoid overdoses. | Medical skill, chemistry knowledge, triage speed |
| Security Officer | A | Man turrets during creature encounters, grab weapons during boarder events, and patrol the submarine for threats. | Weapons skill, reaction time, turret accuracy |
| Mechanic | A | Respond to hull breaches immediately, weld repairs under pressure (sometimes while the compartment floods), and maintain mechanical systems between emergencies. | Mechanical skill, welding speed, diving ability |
Captain (S-Tier): The Captain navigates, sets heading, and commands the crew. Good Captains know the cave systems, avoid creature spawns, and manage crew morale. The Captain's navigation directly determines mission success — bad pathing leads to monster encounters and dead ends.
Engineer (S-Tier): Engineers manage the reactor — the submarine's heart. Reactor output must match power demand: too low and systems fail, too high and the reactor overloads (meltdown). Wiring knowledge lets Engineers fix electrical systems and create custom circuits.
Medic (S-Tier): Medics treat injuries (bleeding, bone fractures, organ damage), cure diseases, and craft medical supplies. The medical system is detailed — wrong drugs cause overdoses, and untreated injuries worsen. A good Medic keeps the crew alive through extended missions.
Security Officer (A-Tier): Security Officers man turrets, fight creatures that board the sub, and handle hostile crew in multiplayer. The Railgun (submarine turret) deals massive damage to creatures. Personal weapons (Revolver, SMG) handle boarders inside the sub.
Mechanic (A-Tier): Mechanics repair hull breaches, fix mechanical systems, and maintain the submarine's physical integrity. Hull breaches cause flooding that cascades through the sub. Quick welding repair is often the difference between sinking and surviving.
For full build breakdowns with gear and stat priorities, see our Barotrauma builds guide.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| Revolver | The standard sidearm for Security Officers. | Security Officer |
| SMG | A rapid-fire weapon with a large magazine. | Security Officer |
| Stun Baton | A melee weapon that stuns creatures and hostile crew. | Security Officer |
| Harpoon Gun | An underwater weapon effective in diving encounters. | Security Officer |
| Railgun | The submarine's mounted turret weapon dealing massive damage to large creatures. | Security Officer |
Revolver: The standard sidearm for Security Officers. Reliable damage against Mudraptors and boarders. Six shots before reloading. The Revolver is the most common personal weapon found at outposts.
SMG: A rapid-fire weapon with a large magazine. Less damage per shot than the Revolver but higher sustained fire rate. Effective against multiple boarders. Ammo consumption is the main downside.
Stun Baton: A melee weapon that stuns creatures and hostile crew. Non-lethal option for subduing infected crew members. The stun effect prevents actions for several seconds, creating windows for injection or restraint.
Harpoon Gun: An underwater weapon effective in diving encounters. The Harpoon Gun works outside the submarine where other weapons don't. Essential for defending divers during exterior repairs or ruin exploration.
Railgun: The submarine's mounted turret weapon dealing massive damage to large creatures. The Railgun requires a dedicated operator and uses the sub's power supply. One well-placed Railgun shot kills Mudraptors and damages Molochs significantly.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| Europa | All depths | Campaign progression, creature encounters, resource collection |
| Submarine Interior | All missions | Systems access, crafting stations, storage, survival |
| Ruins | Mid-late campaign | Alien artifacts, rare materials, unique equipment, highest value loot |
| Abyss | Late campaign | Rare resources, endgame content, Endworm encounters |
| Outpost | Between missions | Resupply, crew hiring, submarine repairs, mission selection |
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.
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.
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.
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.
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.
Tips That Actually Matter
- 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.
- 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.
- Water flooding spreads through connected compartments via doors. Close bulkhead doors during breaches to contain flooding. Pumps remove water but consume significant battery power.
- 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.
- 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.
- Husk parasites infect crew members through bites, eventually turning them hostile. If a crew member is bitten, the Medic must treat them with Calyxanide before full infection. Watch for behavioral changes.
- Creature weak points deal extra damage. Mudraptors take bonus damage to the head. Learn each creature's weak point for efficient combat.
- Voice communication (in-game proximity chat) adds immersion and coordination. Call out threats, request help, and coordinate repairs verbally. Silent crews die more often.
- In multiplayer, griefers exist. The Security Officer doubles as crew police. Stun Batons and handcuffs handle saboteurs without lethal force.
- Submarine upgrades between missions (better reactor, hull reinforcement, turret improvements) are the most impactful long-term investments. Prioritize reactor stability and hull integrity.
Common Mistakes to Avoid
- 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.
Frequently Asked Questions
Is Barotrauma fun solo?
Solo play uses AI crew bots that handle basic roles (reactor, repairs, medical) with configurable behavior. It works but lacks the chaos and coordination of multiplayer. The game is designed for 2-6 player co-op and shines with a full human crew.
How many players does Barotrauma support?
Up to 16 players per submarine, with dedicated servers supporting larger communities. The optimal crew size is 3-6 players. Larger crews divide roles more specifically while smaller crews multi-task between roles.
Is Barotrauma scary?
Yes, genuinely. The combination of underwater darkness, creature attacks, hull breaches, and crew panic creates authentic horror. The sound design (groaning hull, distant creature calls) builds tension constantly. Husk infection events are particularly unsettling.
What submarine should beginners use?
The Dugong is the recommended starter submarine — small, simple layout, and forgiving systems. Graduate to the Typhon or Berilia as you learn. Custom submarines from the Steam Workshop offer varied experiences.
What to Read Next
- Best Barotrauma Builds — Detailed breakdowns with gear, stats, and playstyle guides
- Barotrauma Tier List — Current meta rankings
- Barotrauma Walkthrough — Step-by-step progression from start to endgame
- Barotrauma Beginner's Guide — First session essentials
- Barotrauma Tips & Tricks — Advanced strategies and hidden mechanics
