Subnautica Tips: How to Survive the Ocean Without Dying of Thirst (or Leviathans)

Subnautica is a game that demands you learn by dying. Not in the roguelike way where you restart runs — in the way where you leave your Lifepod without a water bottle, die of dehydration in the kelp forests, reload, forget again, die again, and eventually realize the ocean is trying to kill you in fifteen different ways simultaneously.

Here's what I wish I'd known going in. No major story spoilers, just the practical survival knowledge that makes the first thirty hours less miserable. If you've never played before, read carefully. If you bounced off once and want to try again, this is the primer.

The first hour is crucial

When you drop into the Lifepod after the crash, the game immediately starts punishing you for not knowing anything. Here's your absolute priority list for hour one:

Swim out to your Lifepod's surroundings immediately. Pick up every piece of Acid Mushroom you can find in the Safe Shallows — they go into batteries and eventually the sea bases you'll need. Grab Titanium from wrecked fragments (the broken crates and debris scattered around). Pick up Scrap Metal and break it into Titanium at the fabricator.

Build a Survival Knife. Build a Repair Tool. Build a Scanner. These three plus the fabricator cover your early essentials.

Find clean water and food. You start starving and dehydrating immediately. Bladderfish give you water when you grab them. Peepers give you food. Shallow water cooked fish is easier and faster than anything else early. Don't waste filters and disinfected water filters yet — those come later.

Fear is a game mechanic

Subnautica's scariest moments aren't combat. They're you, alone, hearing a Reaper Leviathan roar somewhere nearby and trying to figure out if it's getting closer. The game uses audio as your warning system in ways most games don't. Listen for the distinctive sounds of dangerous creatures. Reapers have a specific roar. Warpers have a specific teleport sound. Ghost Leviathans make the water feel heavier before you see them.

Your Seaglide has a sonar function — use it constantly in deep or dark water. It pings out a short-range map showing where creatures and terrain are. This is the closest thing Subnautica gives you to "look where you're going" and it's essential for surviving leviathan-infested biomes.

Build your base in the right place

Everyone wants to build a cool base. Most people build it wrong. Here are the rules:

The Grand Reef and Jellyshroom Caves look cool but they're terrible for early bases — too far from resources, leviathans nearby, power is complicated. The Safe Shallows are boring but they're safe. Pick somewhere between the Safe Shallows and Kelp Forest for your main base.

Your base needs: a Multipurpose Room (big round room with lots of upgrade space), a Solar Panel (free energy near the surface), a Water Filtration Machine (infinite water eventually), a Fabricator inside, a Medical Kit Fabricator, and storage lockers labeled clearly.

Depth matters. Solar panels lose efficiency below 100m deep. Power transmitters solve that but cost materials. Thermal plants are great near hydrothermal vents. Bioreactors (fed on fish) work anywhere but are inefficient. Don't try to build a base at 500m depth until you've mastered the shallower one.

Vehicle progression is the whole game

You start with the Lifepod. You eventually build a Seamoth, then a Prawn Suit, then a Cyclops. Each unlocks deeper exploration and new biomes.

The Seamoth is your workhorse. Fast, nimble, decent depth module upgrades. You're not ready for deep exploration without one. Priority: build the Seamoth as soon as you've got the Mobile Vehicle Bay and fragments.

The Prawn Suit is for deep exploration and mining. It has drill attachments, grapple arms, and jump jets. Looks ridiculous, works amazingly. You'll love the first time you grapple onto an Aurora wreck from 200m below.

The Cyclops is a mobile base. Huge, slow, consumes power, can be hidden in silent running mode to sneak past leviathans. Not actually necessary to beat the game but feels incredible to drive.

Leviathans and how to survive them

Eventually you will encounter a Reaper Leviathan. The first time you do it will be terrifying. Here's how to not die:

Reapers are territorial. Once you know where one lives, stay out of that zone. Reapers cannot follow you into caves or deep shallow water. Your Seaglide is faster than a Reaper's chase speed if you have the courage to not panic.

Ghost Leviathans patrol specific paths. Their roar precedes them by seconds. If you hear one nearby, dive into a canyon or drop below their patrol depth.

The Sea Dragon Leviathan in the Inactive Lava Zone is the scariest encounter in the game. The Prawn Suit with thermoblade and grapple can fight back. Running is usually better.

Aggressive leviathans (Reapers, Ghost Leviathans) can kill you in 2-3 hits. Passive leviathans (Sea Emperor, Reefbacks) are harmless. Always know which you're dealing with.

The tech tree guides the story

Subnautica has a story but it's told through PDA logs, radio messages, and what you find in the world. The tech tree progression — going from Seaglide to Seamoth to Prawn Suit to Cyclops to deeper gear — is how the story unfolds. If you skip fragment hunting in favor of rushing objectives, you miss half the game.

Follow the radio signals. Explore the wrecks. Scan everything. The game tells you what to build next if you pay attention.

Don't rush the main quest

There's a point in the game where following the main objectives can trap you in a situation you're not equipped for. The Lost River, the Inactive Lava Zone, the Primary Containment Facility — all of these punish underleveled players badly.

Build up your vehicle fleet before pushing main quest objectives. The Cyclops with a thermoblade Prawn Suit in its docking bay is what you want before descending into the deep biomes.

Oxygen is a resource, not a decoration

Early game you can hold your breath for maybe two minutes. Upgrades and gear extend this. But the game is relentless about reminding you that humans don't breathe water. Always plan your dives around your oxygen budget. A pipe network from the surface through caves lets you refill mid-swim without surfacing. The Seamoth holds enough oxygen to dive for hours.

Dying from oxygen starvation is the most common death in Subnautica. Always know where your exit is.

Below Zero is different

Subnautica: Below Zero is the standalone expansion/sequel. It changes up the formula — Arctic setting, smaller map, faster pacing, new vehicles (Sea Truck replaces Cyclops). Play the original first, then Below Zero.

What we're working on at Choost

Subnautica's survival loops have influenced a lot of what we think about in game design. The way it teaches through discovery rather than explicit tutorials is something we try to carry into our games. Granny's Rampage has a smaller version of that "learn by dying" progression, just with fewer leviathans. For the broader survival genre, the best exploration games post has more recommendations.

The shortest version

Prioritize water and food first hour. Build a Seaglide before anything else. Always have your Repair Tool ready. Listen for leviathan audio cues. Scan every fragment. Build a base between Safe Shallows and Kelp Forest. Progress through vehicles: Seaglide → Seamoth → Prawn Suit → Cyclops. Follow the radio signals. Oxygen management is survival.

And the most important tip of all: play with headphones. The audio design carries the entire experience. Subnautica on speakers loses so much of what makes it scary and beautiful.