Subnautica: Below Zero is the standalone follow-up to Subnautica, set in an arctic region of planet 4546B. You play as Robin Ayou investigating her sister's death at an Alterra research station while an alien entity named Al-An shares your mind. The game adds significant land-based exploration across frozen tundra alongside the underwater gameplay, plus the Seatruck — a modular submarine where you attach different functional modules (storage, fabricator, aquarium, sleeper) to create a custom mobile base. Below Zero is smaller and more focused than the original, with a tighter story and less open exploration.
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
Seatruck modules
The Seatruck is a modular vehicle where each module attaches behind the cabin. Modules include: Aquarium (stores fish), Storage (extra inventory), Fabricator (crafting on the go), Sleeper (bed for time skip), and Docking (carries Prawn Suit). Adding modules makes the Seatruck slower but more capable. You can detach modules for speed in dangerous areas.
cold resistance
Land exploration in Below Zero requires managing body temperature. Cold exposure reduces health over time. Heat sources (fires, thermal springs, heated bases) warm you. Cold-resistant gear (Snowfox hoverbike, cold suit) extends exploration time. Some biomes have extreme cold that requires active heat management.
alien research
Al-An (an alien stored in your brain) guides you to find components for building him a new body. This questline runs parallel to Robin's investigation of her sister's death. Alien facilities contain technology blueprints, story logs, and materials for Al-An's body parts (tissues, skeleton, organs).
base building
Same modular system as Subnautica — multipurpose rooms, corridors, observatories, powered by solar, thermal, or nuclear. Below Zero adds land-based building with cold management. Bases need heating in arctic biomes. The Thermal Plant (built near heat vents) provides efficient free power.
creature scanning
The Scanner tool catalogs every creature, plant, and mineral. Scanning provides behavioral data, weaknesses, and crafting opportunities. The PDA entries from scanning build the world's ecology. Full creature scans unlock bonus resources or crafting options.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Deep Explorer | S | Push deeper with each expedition, scan everything new, and use the Prawn Suit for the deepest biomes where the Seatruck can't reach. | Depth rating, oxygen capacity, vehicle power |
| Base Builder | A | Scout beautiful locations, build aesthetically impressive bases, and create a network of outposts connected by Seatruck travel. | Hull integrity, power generation, heating |
| Speedrunner | B | Follow the optimal route through story triggers, skip optional content, and collect only essential resources. | Speed, route memorization, oxygen capacity |
| Completionist | A | Systematically explore each biome, scan every creature and plant, collect every log, and build every craftable item. | Exploration coverage, creature scanning, PDA log collection |
| Lore Hunter | A | Follow both the Robin investigation and Al-An body-building questlines, visiting every marked and unmarked location for story fragments. | Story location knowledge, alien facility access, audio log collection |
Deep Explorer (S-Tier): Focus on reaching maximum depth with upgraded Seatruck (depth modules) and Prawn Suit. The deepest biomes contain the most valuable story content and resources. Depth Module MK3 reaches 900m+ on the Seatruck and 1300m on the Prawn Suit.
Base Builder (A-Tier): Build elaborate underwater and surface bases with full amenities. Below Zero's building system adds glass corridors, observatories, and land-based modules. Thermal plant placement near heat vents provides unlimited power. The Large Room module enables expansive interior designs.
Speedrunner (B-Tier): Below Zero can be completed in under 2 hours by beelining to key locations. The Seaglide carries you through early game, and memorized blueprint locations skip exploration. The Snowfox hoverbike speeds up land sections. Story-critical items have fixed locations.
Completionist (A-Tier): Scan every creature, find every PDA log, explore every cave, and build every item. Below Zero has a smaller world than the original, making 100% completion more feasible. The datapad trail tells a complete story when all logs are found.
Lore Hunter (A-Tier): Focus on finding every PDA log, alien artifact, and story fragment. Below Zero's dual storyline (Robin/Al-An) has dozens of voice logs and data entries scattered across the world. Lore Hunters prioritize story locations over resource gathering.
For full build breakdowns with gear and stat priorities, see our Subnautica: Below Zero builds guide.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| Survival Knife | Basic tool for harvesting coral, plants, and defending against small predators. | All builds |
| Seatruck Perimeter Defense | A module that creates an electric pulse around the Seatruck, stunning and repelling aggressive creatures. | Deep Explorer |
| Prawn Suit | An underwater mech suit with drill arms for mining Large Resource Deposits and grapple arms for traversal. | Deep Explorer |
| Spy Pengling | A deployable robotic penguin that scouts areas remotely through a camera feed. | Completionist |
| Scanner | Scans creatures, plants, and fragments to add them to your PDA database and unlock blueprints. | All builds |
Survival Knife: Basic tool for harvesting coral, plants, and defending against small predators. Upgradeable to Thermoblade for fire damage and instant fish cooking. Essential for collecting crafting materials from flora and fauna.
Seatruck Perimeter Defense: A module that creates an electric pulse around the Seatruck, stunning and repelling aggressive creatures. Essential for traversing biomes with Chelicerate or Shadow Leviathans. Uses Seatruck power reserves.
Prawn Suit: An underwater mech suit with drill arms for mining Large Resource Deposits and grapple arms for traversal. Walks on the ocean floor and withstands deep pressure with upgrades. The Drill Arm mines 10x faster than the knife.
Spy Pengling: A deployable robotic penguin that scouts areas remotely through a camera feed. Use it to explore dangerous areas (Leviathan territories) without risking your character. Can fit through small spaces you can't.
Scanner: Scans creatures, plants, and fragments to add them to your PDA database and unlock blueprints. The most important tool in the game — scan everything you encounter. Blueprint fragments require scanning 2-3 pieces to complete the recipe.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| Twisty Bridges | 0-100m depth | Basic resources, early blueprints, Seatruck fragments, safe base location |
| Lilypads | 100-300m depth | Seatruck modules, Magnetite, Ventgarden encounter |
| Crystal Caves | 300-600m depth | Ion Cubes, Nickel Ore, deep base resources, story progression |
| Glacial Basin | Surface (cold damage) | Snowfox blueprints, Al-An tissues, Phi Robotics story logs |
| Fabricator Caverns | 600-1000m depth | Al-An body construction, final alien technology, deepest exploration content |
Twisty Bridges: The starting biome with winding coral bridges and abundant basic resources. Safe and well-lit with minimal predator threats. Contains early blueprint fragments and the initial story triggers. Build your first base here.
Lilypads: A mid-depth biome with massive lily pad structures and the Lilypad Islands on the surface. Contains Seatruck fragments and moderate-danger predators. The Ventgarden creature inhabits a massive cave system here.
Crystal Caves: A deep biome with bioluminescent crystals and dangerous fauna. Contains rare resources (Ion Cubes, Nickel Ore) needed for advanced crafting. The Crystal Caves connect to the Fabricator Caverns and deeper story locations.
Glacial Basin: A frozen surface area with ice caves, Snowstalkers (land predators), and the Phi Robotics Lab. Requires cold-resistance gear. Contains Al-An story progression and the Snowfox hoverbike blueprints. The weather system creates dangerous blizzard conditions.
Fabricator Caverns: The deepest biome containing ancient alien fabrication equipment. Al-An's body construction happens here. Contains the most dangerous deep-sea creatures and the most valuable alien technology. This is where the Al-An questline concludes.
Tips That Actually Matter
- Build the Seatruck before anything else — it provides safe transport, oxygen, and storage. The base Seatruck (no modules) is fast and maneuverable enough for early exploration.
- Detach Seatruck modules before entering dangerous areas. The base cabin alone is much faster than the full modular train. Reattach modules at your base.
- Thermal Plants placed near underwater heat vents generate unlimited free power. Build your main base near a vent cluster for permanent energy.
- The Spy Pengling is legitimately useful — deploy it near Leviathan territories to scout safe paths without risking your life or vehicle.
- Cold damage on land is managed by: staying near heat sources, wearing the cold suit, building fires with the Flare, and using the Snowfox's heated cabin.
- Al-An's dialogue triggers at specific locations and story milestones. Explore alien facilities thoroughly to advance his questline alongside Robin's investigation.
- The Mineral Detector (crafted tool) reveals nearby resource deposits through walls and terrain. Essential for finding rare minerals in deep biomes.
- Creature eggs can be placed in the Alien Containment (large fish tank) to hatch and study. Some hatched creatures provide useful resources when they mature.
- The Prawn Suit's grapple arm provides Spider-Man-like traversal underwater — grapple to walls and ceilings for rapid movement through cave systems.
- Below Zero's world is smaller than the original Subnautica. This means you can feasibly explore every biome and find every secret in a single thorough playthrough.
Common Mistakes to Avoid
- Not building a Seatruck early — swimming everywhere wastes oxygen and exposes you to predator attacks. The Seatruck is your first major crafting priority.
- Ignoring cold management on land — cold damage adds up quickly. Always carry a Flare and wear the cold suit in the Glacial Basin.
- Attaching too many Seatruck modules — more modules = slower vehicle. Only attach modules you need for the current expedition. Leave others at base.
- Missing Al-An's body parts — his questline runs parallel to the main story. If you don't visit alien facilities, his story stalls. Follow both quest threads simultaneously.
- Building a base in a predator-heavy area — Chelicerates and Shadow Leviathans attack vehicles near your base. Build in calm biomes like Twisty Bridges or Thermal Spires.
Frequently Asked Questions
Is Below Zero as good as the original Subnautica?
Below Zero is a smaller, more focused experience with a tighter story and better voice acting. The original has a larger world and more iconic moments (first Reaper encounter). Most players rate the original higher overall, but Below Zero's land exploration and Al-An storyline are excellent additions.
How long is Subnautica: Below Zero?
Main story takes 15-25 hours. Completionist exploration adds 5-10 hours. Speedruns complete in under 2 hours. It's roughly half the length of the original Subnautica, reflecting its tighter design focus.
Do I need to play the original Subnautica first?
Recommended but not required. Below Zero has story connections to the original (same planet, referenced events), and the gameplay mechanics build on the first game's systems. Playing the original first makes certain story reveals more meaningful.
Is Below Zero scary?
Less consistently scary than the original. The arctic setting is more alien than terrifying. However, deep-sea encounters with Shadow Leviathans and Chelicerates still trigger thalassophobia. The Crystal Caves darkness creates genuine tension.
What to Read Next
- Best Subnautica: Below Zero Builds — Detailed breakdowns with gear, stats, and playstyle guides
- Subnautica: Below Zero Tier List — Current meta rankings
- Subnautica: Below Zero Walkthrough — Step-by-step progression from start to endgame
- Subnautica: Below Zero Beginner's Guide — First session essentials
- Subnautica: Below Zero Tips & Tricks — Advanced strategies and hidden mechanics
