Subnautica: Survival Guide

A spoiler-light survival guide to the original Subnautica: your first hours in Lifepod 5, what to craft and in what order, vehicle and depth progression, base building, the leviathans, and the path to escaping planet 4546B. Story beats in the later sections are marked.

Researched September 2026 — current as of the October 2025 security hotfix build (the "Living Large" 2.0 feature set, plus the August 2025 patch). Live games change; check the linked sources if something differs.

Status (September 2026): Subnautica is finished and only gets maintenance patches. In October 2025, Unknown Worlds released a security hotfix for a Unity vulnerability and disabled all legacy and alternative branches (including the speedrunning branch). If you use mods, they must support the current build, so back up your saves before updating. The sequel, Subnautica 2, entered Early Access on May 14, 2026 (PC and Xbox Series X|S), with optional 4-player co-op. This guide covers the original game.

Quick Start

1. Pick your mode:
   • Survival: hunger, thirst and oxygen, and you drop items on death.
   • Freedom: no food or water.
   • Hardcore: one life, and the save is deleted when you die.
   • Creative: everything is unlocked. Freedom is a great first run if you just want to explore.
2. Scan everything. The Scanner is how you learn blueprints. Fragments of vehicles and tools lie around wrecks, and scanning enough of them unlocks the blueprint.
3. Craft the essentials in this order: Scanner, Survival Knife, Standard O2 Tank, Fins, Repair Tool. Then the Seaglide, then the Mobile Vehicle Bay and the Seamoth.
4. Stay near the lifepod early. The Safe Shallows and Kelp Forest have everything you need for the first couple of hours.
5. Don't go near the Aurora wreck until it explodes and you have a Radiation Suit. The game tells you when it's safe to approach.
6. Oxygen is the real clock. Surface before the warning. Air bladders, pipes from a base, and vehicles all give you more margin.
7. Save manually and often. Especially before deep dives and before exploring wrecks.
8. Night is dangerous. Predators hunt more after dark, and it's harder to see. Carry a flashlight, and later use vehicle lights and flares.
9. Leviathans are a "don't go there yet" signal, not a boss fight. If you hear a Reaper roar, back off.
10. Follow the PDA. The radio in your lifepod and your PDA's log point you to the main story locations. Fix the lifepod radio with the Repair Tool to get the rescue messages.

Core Controls (PC defaults)

Controller and input options were reworked in the August 2025 patch. Check Options, Controls if something doesn't match.

Survival Basics

• Cured fish (made with salt) never spoils. Cooked fish does. Cure your food for long trips.
• Lithium, Magnetite, Silver and Gold unlock the good early upgrades. Break outcrops to find ores:
  • Limestone gives titanium and copper.
  • Sandstone gives silver, gold and lead.
  • Shale gives gold, lithium and diamonds.

Early Game Plan (first 2–5 hours)

1. Repair the lifepod (secondary systems) with the Repair Tool. This turns on the radio, which gives you distress calls and story leads.
2. Seaglide: scan fragments in the Safe Shallows and Kelp Forest. It greatly increases your range.
3. Build a starter base: a Multipurpose Room or corridor near the lifepod, with a Solar Panel, Fabricator and lockers. You need a Habitat Builder for this.
4. Mobile Vehicle Bay: scan its fragments, build it on the surface, and it builds your Seamoth.
5. Radiation Suit: craft the full set (suit, helmet and gloves) before approaching the Aurora after it explodes. It protects you from the radiation leak.
6. Explore the Aurora once you have the Radiation Suit, Repair Tool, Fire Extinguisher (fires on board) and ideally the Laser Cutter. The Aurora holds the Prawn Suit and Propulsion Cannon fragments and much more. Look for keypad codes in PDA logs you find along the way. Repair the leaking drive core with the Repair Tool: that stops the radiation from spreading.

Vehicles and Depth Upgrades

• Upgrades: you build depth MK1 at the Vehicle Upgrade Console (or the Cyclops Fabricator for the Cyclops). MK2 and MK3 are made at the Modification Station by upgrading the previous module.
• Seamoth modules: the Perimeter Defense System zaps anything that grabs you and saves lives against Reapers. Storage modules double as extra lockers. The Sonar helps in dark caves.
• Prawn Suit arms: the Grappling Arm for mobility, the Drill Arm for large resource deposits, and the Propulsion Arm for moving objects. Add Jump Jet upgrades for cave climbing.
• Cyclops: noise and light attract leviathans. Run silent (lights off, slow speed), install the Shield Generator, and turn engines off when something big is nearby. Install the Fire Suppression System too.

Base Building

• Hull integrity drops the deeper you build. Reinforcement and Bulkheads raise it. Glass pieces (windows, glass corridors, domes) lower it.
• Power sources:
  • Solar: shallow water only.
  • Bioreactor: burns organic matter.
  • Thermal Plant: needs heat from vents and lava.
  • Nuclear Reactor: late game.
• Key rooms and modules:
  • Scanner Room: finds resources and fragments within range, and its camera drones scout for you.
  • Moonpool: docks vehicles and charges them.
  • Water Filtration Machine
  • Alien Containment: for breeding fish and a later story step.
  • Large Room and Glass Dome: added in the 2.0 "Living Large" update.
• Put a forward base near the Lost River entrance or the Jellyshroom Cave. A charging Moonpool at depth makes the midgame much safer.

Biomes, Resources and Threats

Passive giants: Reefbacks and Sea Treaders won't hurt you. Sea Treaders knock loose resources on their path.

Story Path (spoiler-light)

1. Rescue signals and the Degasi: radio messages send you to lifepods and three Degasi survivor habitats (Floating Island, Jellyshroom Cave, Deep Grand Reef). Their logs tell you what happened before you.
2. The alien gun: on Mountain Island you find the Quarantine Enforcement Platform. It's why the Aurora crashed, and why you can't leave.
3. The infection: you're infected with the Kharaa bacterium. The alien research sites hold the lore and tech.
4. Going deep: the Disease Research Facility (Lost River), the Thermal Power Facility (Inactive Lava Zone) and the Primary Containment Facility (Lava Lakes) take you steadily deeper. Ion Cubes, alien tablets and Prawn/Cyclops depth upgrades are your gates.
5. The cure and escape: hatching the Sea Emperor's eggs produces Enzyme 42, which cures you and lets you disable the gun. Then you build the Neptune Escape Rocket to leave.

Useful mid-game tech: the Ion Battery and Ion Power Cell (from Ion Cubes) power your tools and vehicles far longer.

Common Mistakes to Avoid

• Diving deep without backup oxygen. Carry a spare tank or build a pipe line, and never push the O2 warning in a cave.
• Leaving the Seamoth or Prawn Suit parked in Reaper territory or below their crush depth.
• Building a deep base with a lot of glass and forgetting Reinforcement. Hull breaches flood rooms.
• Ignoring the Scanner Room. It saves hours of hunting for magnetite, lithium, silver and fragments.
• Letting food rot. Cure fish before long expeditions, or set up grow beds.
• Overusing the Cyclops lights and engines around leviathans.
• Not reading PDA logs. Door codes and story directions live in them.

Advanced Tips

• Beacons: drop them at wreck entrances, cave openings and outposts. Color-code and rename them.
• Waterproof Lockers can sit outside your base or near a dig site as caches.
• Stasis Rifle: freezes anything, including leviathans, long enough to escape.
• The Seamoth Perimeter Defense System plus the Stasis Rifle is the classic Reaper-escape kit.
• Thermal Plants near lava are the most reliable deep power. Pair them with a Moonpool for charging.
• Fruit farms: Lantern Fruit (Floating Island) and Marblemelon (Degasi habitats) regrow, which ends food worries.
• Use the in-game Unstuck button (added in 2.0) if you clip into terrain.
• Mods: after the October 2025 hotfix, only mods updated for the current build work. Disable old mods before launching.

FAQ

When is it safe to explore the Aurora? After the drive core explodes and you've crafted the Radiation Suit. The game's radio messages and PDA prompts walk you through it.

Is there multiplayer? Not in the original game. Subnautica 2 (Early Access since May 14, 2026) adds optional co-op for up to four players.

How do I kill a Reaper Leviathan? You mostly shouldn't. Avoid them, or escape with the Seamoth Perimeter Defense System and the Stasis Rifle. Late-game weapons can kill one, but it's rarely worth it.

What's the max safe depth for each vehicle? Seamoth 900 m with MK3, Prawn Suit 1700 m with MK2, Cyclops 1700 m with MK3 (see the table above).

Why can't I leave the planet? The alien Quarantine Enforcement Platform shoots down anything that tries to leave while the infection is active. Curing yourself and disabling it is the core of the story.

Does Subnautica still get updates? Only maintenance: a 2025 patch ported fixes from the mobile version, and there was a security hotfix in October 2025. New content is in Subnautica 2.

Sources

• Subnautica on Steam
• Steam news: Security Hotfix (Oct 2025), 2025 Patch, Living Large update
• Wikipedia: Subnautica
• Wikipedia: Subnautica 2