Important Notes

Warnings and Pitfalls

Oxygen and Depth: Always monitor your oxygen and depth meter. Venturing too deep without a vehicle or proper upgrades (e.g., Seamoth depth module, Rebreather, Ultra High Capacity Tank) leads to quick drowning.

Radiation: After the Aurora explosion, the area around the ship emits lethal radiation. Craft a Radiation Suit (from fragments in the Safe Shallows and Kelp Forest) before exploring the Crash Zone. Without it, you'll take rapid damage.

Food and Water: Hunger and thirst deplete faster than you expect. Early on, rely on fish (cooked or cured) and bladderfish (for water). Build a fabricator and a knife immediately.

Creature Aggression: Many creatures are territorial but not hostile unless provoked. Blades and perimeter defense systems are your friends. Leviathans (Reapers, Ghosts, Sea Dragons) are extremely dangerous; avoid their patrol routes if possible.

Hull Integrity: When building bases, monitor hull integrity. Overloading with modules without reinforcements will cause leaks and flooding. Start with a simple room and add reinforcements (foundation, reinforcements, or bulkheads) as you expand.

Fire in the Lifepod: When you first arrive, the Lifepod is on fire. Use the fire extinguisher (located next to the fabricator) to put it out immediately. If ignored, the fire will destroy the Lifepod.

Irreversible Choices

Time Capsule Submission: You can send only one time capsule per save file. Choose your items wisely—often players regret not including late-game gear or rare items. Once sent, it cannot be undone.

Consuming Rare Resources: While no resource is truly finite on 4546B, some are extremely scarce and respawn only slowly or not at all (e.g., Ion Cubes, Kyanite, Nickel Ore). Crafters may regret using these items for experimental builds before they have enough for critical upgrades like the Prawn Suit depth modules.

Deconstructing Bases: You can deconstruct most base pieces, but the resources are returned. However, if you build in a dangerous location and then deconstruct, you may waste time. No permanent loss, but time is valuable.

The Quarantine Enforcement Platform: You must eventually disable it to leave the planet. There is no alternative route; this is not a choice but a required step.

Missable Content

Data Boxes in Wrecks: Wrecks contain crucial blueprints (e.g., Fragment Scanner, Vehicle Modification Station). Some are in deep or radiation-filled areas that you might skip early.

Degasi Bases: The three Degasi bases (on the Floating Island, in the Jellyshroom Cave, and in the Deep Grand Reef) contain PDA logs that expand the story. Missing them leaves plot gaps.

Cuddlefish Eggs: There are exactly five Cuddlefish eggs scattered across the map. Hatching one gives a loyal pet, but collectors may regret not finding all. Use a scanner room to locate them.

Aurora Drive Core and PRAWN Suit Bay: Inside the Aurora, you can find the PRAWN Suit bay and the drive core PDA. If you delay exploration, the radiation subsides but the interior remains dangerous. Nothing is lost, but you may miss easy access.

Time Capsules from Other Players: While not missable per se, many players never build a time capsule dispenser (requires a modification station) and thus never receive any. Build it to gain random late-game gifts.

Difficulty Spikes

Early Aurora Exploration: Entering the Aurora requires a radiation suit, propulsion cannon (to clear scrap), and fire extinguisher. The interior has high heat, Cave Crawlers, and Biter fish. Be prepared with medkits and a repair tool.

The Crash Zone (Reaper Leviathans): The waters around the Aurora are patrolled by aggressive Reapers. Their grab attack can destroy the Seamoth instantly. Use a sonar upgrade or stay near the surface to avoid them.

Lost River and Lava Zones: The Lost River is a transition zone to the deep biomes. Despite appearing calm, it contains Ghost Leviathans (both juvenile and adult). Without a Cyclops or Prawn Suit with depth upgrades, you will struggle.

Warpers: These teleporting creatures in the Inactive Lava Zone and Deep Grand Reef can teleport you out of your vehicle, leaving you vulnerable. Keep a stasis rifle ready.

Sea Dragon Leviathans: Found in the Lava Lakes and Inactive Lava Zone. They can deal massive damage to the Cyclops and Prawn Suit. Evade their fireballs and use a decoy if necessary.

Oxygen Management at Depth: Beyond 200m, oxygen consumption increases without a Rebreather. At 500m+, even with high-capacity tanks, you have only minutes. Plan your dives carefully.

Grinding Traps

Over-Collecting Early Resources: Titanium, quartz, and copper are common in the Safe Shallows. Don't hoard them endlessly—your storage is limited. Instead, stock only what you need for immediate crafting.

Excessive Base Building Prematurely: Building a large base before you have a seamoth, beacon, or scanner room wastes time and resources. Start with a simple multipurpose room, two lockers, and a fabricator. Expand only after you have vehicles.

Manual Resource Gathering vs. Scanner Room: Many players spend hours swimming to gather ore manually. Building a scanner room with a range upgrade automatically marks nearby deposits, saving immense time.

Farming Fish for Food: Fishing manually is inefficient. Build an alien containment unit or an exterior growbed to propagate fish (e.g., Reginalds for high food value) and plants.

Battery/Power Cell Over-Crafting: Early on, batteries and power cells are expensive (copper, lead). Instead, craft a battery charger and power cell charger as soon as possible. Reuse your cells.

Killing Every Creature: Aggressive creatures respawn slowly. Killing Reapers or Ghosts is possible but requires significant time and ammunition. It's often better to avoid them.

Online Etiquette and Anti-Cheat

No Multiplayer or Anti-Cheat: Subnautica is strictly a single-player game. There is no official multiplayer, no leaderboards, and no anti-cheat system. Mods (e.g., Nitrox multiplayer mod) are community-made but not supported by the developer. If you use mods, be aware they may cause bugs or save incompatibility.

Time Capsule Etiquette: When sending a time capsule, include items that are useful to new players but not game-breaking. Avoid spoilers in the message (e.g., plot twists) to preserve the experience for others.

No Cheat Police: Debug commands (accessed via F3 and entering “developer” mode) can be used to fix bugs like getting stuck, but using them to cheat may disable achievements permanently in that save. Use responsibly.

Save Management

Save Slots: You have 50 manual save slots. Autosave occurs when you enter a base, enter the Lifepod, and on save-and-quit. Autosaves overwrite the most recent manual save; be careful in Hardcore mode.

Manual Saves: Save manually before any dangerous expedition (e.g., visiting Aurora, going below 500m, entering the Lost River). Also save after major milestones (new vehicle, base extension).

Hardcore Mode: Only one save, auto-saved when you quit. If you die, the save is deleted. No second chances. Use this only if you accept permadeath.

Backup Saves: For extra safety, manually copy your save files from the save directory (e.g., %APPDATA%\Subnautica on Windows). This can prevent loss from corruption.

Avoid Save Corruption: If you notice strange behavior (e.g., terrain not loading, items phasing through walls), reload a previous save rather than continuing.

Things Players Commonly Regret Not Knowing Earlier

1. Scanner Room is Your Best Friend: Build one early to locate resource deposits, wrecks, and creatures. The HUD chip upgrade shows markers on your screen—invaluable.
2. Seaglide is Mandatory: It's cheap (battery, lubricant, copper wire, titanium) and doubles your swim speed. Craft it right after fixing the Lifepod.
3. Leviathans Are Avoidable: Most leviathans have fixed patrol routes. Learn them and stay out of their path. The Stasis Rifle (requires Magnetite) can freeze them for easy passing.
4. The Propulsion Cannon Opens Paths: It can move heavy wreckage, create shortcuts, and even pick up fish. Essential for the Aurora and other wrecks.
5. Build a Moonpool for Vehicle Upgrades: The Moonpool houses the Vehicle Upgrade Console, which allows depth modules, storage upgrades, and perimeter defense. Don't delay.
6. Base Location Matters: Build near key biomes: Safe Shallows for early safety, Kelp Forest for resources, and near the entrance to the Lost River for deep exploration. A central location saves travel time.
7. Beacons Are Cheap, Use Them: Craft beacons (titanium + copper) to mark resource nodes, wrecks, and base locations. Without them, you will get lost.
8. The Bioreactor is Reliable: Before you get nuclear or thermal power, the bioreactor with fish or non-edible plants (e.g., Reginalds, Oculus) provides steady energy without sunlight.
9. Cyclops is Not a Submarine Tank: Treat it like a fragile mobile base. Avoid direct creature attacks, use silent running, and keep decoys ready. Losing it sets you back hours.
10. Prawn Suit Drill Arm for Late-Game Resources: The Prawn Suit with a drill arm can mine large deposits of Kyanite, Nickel, and Uraninite in the Lava Zones. Without it, you’ll struggle for endgame upgrades.
11. Don't Dive Below 200m Without Depth Upgrades: The Seamoth can only go 200m initially. Craft a Vehicle Upgrade Console and modules to increase depth. Diving deeper without them will crush the vehicle and kill you.
12. Craft a Stillsuit for Passive Water: The Stillsuit converts sweat into water. It’s found as a blueprint in the Jellyshroom Cave. Wearing it dramatically reduces the need to carry water bottles.
13. Use a Thermometer: Craft a thermometer to gauge temperatures in thermal vents, which indicate potential thermal power locations.
14. The Best Thermonuclear Power Source is Thermal: When you find the blueprint, build a thermal plant near any heat source (e.g., lava geyser, thermal vent) for unlimited energy without fuel.
15. Don't Throw Away Old Batteries: Use the Battery Charger to refill them. Same for Power Cells. Save resources.
16. The Cuddlefish Can’t Be Replaced: If you hatch one, it will follow you and act cute. If it dies (e.g., eaten by a Reaper), there’s no respawn. Keep it safe in a contained base.
17. Save Before the Sunbeam Event: The Sunbeam landing scene triggers when you approach the Quarantine Enforcement Platform. If you miss it by not being in time, you still get the callback. But saving before lets you reload to experience it fully.
18. Use the Developer Console for Bugs Only: If you get stuck in terrain or lose a vehicle to a glitch, open the console (F3, then uncheck "disable console") and use commands like `warpme` or `submarine`. Overuse ruins the game.
19. Learn the Biomes Early: Each biome has unique resources. For example, the Mushroom Forest gives Lithium while the Blood Kelp Zone gives Uraninite. Knowing where things spawn saves hours.
20. The Aurora Explosion Is Timed: After 11 in-game minutes, the Aurora explodes. You are safe in the Lifepod or a base. After the explosion, radiation spreads. Build the Radiation Suit quickly.