Subnautica 2 Inventory Space Guide: How to Carry More Items

TL;DR

• You start with 20 inventory slots. They fill up in minutes.
• The only way to permanently expand inventory is by using Biobeds inside Colonist Bunkers.
• Each Endurance Biobed gives +3 permanent inventory slots. Three are confirmed in the early game.
• One Dexterity Biobed adds +1 extra tool slot to your hotbar.
• Portable Lockers give 15 extra temporary slots and can be carried around mid-dive.
• Use your hotbar, build base storage, and pack light to stretch your space further.

Inventory space is one of the first walls you hit in Subnautica 2. Resources don’t stack — every item takes up one slot — and you’ll fill up your 20 starting slots within minutes of your first dive. The game never directly explains how to fix this, which means most players spend way too long juggling trips back to base before realizing a permanent upgrade system exists.

This guide covers every method to carry more items, including all confirmed Colonist Bunker Biobed locations, how Portable Lockers work, base storage tips, and the best habits to stretch your inventory as far as possible.

How the Inventory System Works in Subnautica 2

You begin the game with 20 inventory slots and 5 hotbar spaces. Nothing stacks. Titanium, food, water, tools, and crafting materials all compete for the same slots. Your inventory gets tight almost immediately.

The inventory grid only grows when you find and interact with a Biobed terminal inside a Colonist Bunker. There is no craftable backpack. No vendor to buy slots from. Expansion is gated entirely by exploration. Every Biobed you find gives a permanent, stacking bonus that applies immediately and stays with your save forever.

The two upgrade types are:

• Endurance — adds +3 permanent inventory slots.
• Dexterity — adds +1 extra tool slot and hotbar keybind.

Each terminal can only be used once. You need to find multiple Colonist Bunkers to keep expanding.

How to Permanently Increase Inventory Space — Colonist Bunker Biobeds

Colonist Bunkers are abandoned habitats tucked into caves, behind ledges, and near crashed ships across the ocean floor. They are not marked on any map. You navigate to them using direction and distance from your Lifepod, or by following NOA’s black box waypoints, which naturally route you past several of these outposts during normal story progression.

The trick most players miss: the Biobed inside each bunker has a small computer terminal attached to it. Interacting with the bed itself sets your respawn point. But interacting with the terminal screen at the front of the Biobed is what grants the permanent upgrade. Look for the tablet panel — it’s easy to overlook.

When you successfully claim an upgrade, you’ll see the message: “Endurance adapted. Inventory expanded.” Open your inventory with Tab and the three new slots will be visible right away.

Two reliable ways to find Colonist Bunkers:

• Follow blue lightsticks. Glowing blue marker sticks planted in the seabed almost always lead toward a hidden bunker. If you see them, follow them.
• Follow NOA’s black box signals. Several early story waypoints take you directly to or past Colonist Bunkers. Make sure to interact with the Biobed terminal while you’re there before leaving.

All Colonist Bunker Biobed Locations in Subnautica 2

Four Colonist Bunkers are confirmed in the current early access build. Together they give you +9 inventory slots and +1 tool slot on top of your starting 20.

Bunker 1 — Anita’s Garden (100m East-Southeast of Lifepod)

Reward: Endurance — +3 inventory slots.

This is the closest bunker to your starting location. Head east-southeast from the Lifepod. You’ll notice an underwater current that pushes you downward into a cavern. Ride it in. Once inside, look toward the northeastern side of the cavern — there’s a tunnel lined with red kelp. Swim through it to find the bunker. Look for the Alterra crates with the Wakemaker fragment and recording as navigation landmarks nearby.

The interior is modest but the three extra inventory slots are well worth the short trip. It can be a tight cave dive, so having a few oxygen upgrades helps. See our guide on how to increase oxygen in Subnautica 2 before attempting caves.

Bunker 2 — Unauthorized NOA Modification (250m South-Southeast of Lifepod)

Reward: Dexterity — +1 tool slot and extra hotbar keybind.

Also contains: Scannable Repair Tool fragment, Habitat Builder fragment, Rebreather, Tadpole Fragment, Copper Wire, and Advanced Wiring Kit.

This is the most rewarding bunker for early-game progression. The cave entrance is near the Angel Comb Adaptation — look for a cave opening next to a ledge with Alterra equipment. Swim to the bottom of the opening and look left to find the hatch. It’s inside a cave guarded by a Coral Crab, so stay cautious on entry.

The Habitat Builder and Repair Tool fragments here are genuinely useful if you haven’t found them yet. Don’t skip this one. Bring your Scanner to grab everything.

Bunker 3 — Chap Blackbox Bunker (250m South-Southeast of Lifepod)

Reward: Endurance — +3 inventory slots.

Also contains: Scannable Bioreactor fragment.

This bunker is tied to the early objective where NOA sends you to find the Chap blackbox recording. There’s a good chance you’ll pass right through it during normal story play. The entrance is inside a cave with a Coral Crab guarding it. Look for the set of pillars jutting out of the top of a plateau as a surface landmark to help you orient before diving in. Grab the Bioreactor scan while you’re there for future base-building knowledge.

Bunker 4 — Crashed Ship Bunker (300m South-Southwest of Lifepod)

Reward: Endurance — +3 inventory slots.

This is the furthest of the four confirmed bunkers from your Lifepod. The hatch is jutting out of a ridge near the seafloor, close to a crashed ship. Head south-southwest until you spot the wreckage on the seafloor, then look for the hatch poking out of a nearby rock ridge. The bunker itself is straightforward once you’re inside.

After claiming all four Biobeds, your inventory grows from 20 to 29 slots, and your hotbar gains an extra tool slot. More bunkers may be added in future updates as the game progresses through Early Access.

Portable Lockers — Your Best Early Inventory Solution

While you’re hunting Biobeds, Portable Lockers are the best short-term fix for inventory pressure. Each one holds 15 items. You can carry one in your hands while swimming to store materials mid-dive, then bring the whole thing back to base when you’re done.

The downside: you can’t use tools while holding a Portable Locker. But the extra carrying capacity is worth it, especially on resource-gathering runs where you’re just picking things up rather than using equipment.

There is a free Portable Locker at the bottom of the cave directly underneath your Lifepod. It’s one of the earliest inventory upgrades you can grab and requires no crafting. This cave locker also respawns periodically, so you can grab multiple early on to stock your base with storage before building proper lockers.

Once you have the Habitat Builder, you can also craft your own Portable Lockers. The recipe costs 4x Titanium and is found under the Utility section. They are cheap to make and very useful on any serious gathering trip. For Titanium, see our guide on how to get Titanium in Subnautica 2.

Later in the game, you can attach a Portable Locker to the hardpoint on the back of your Tadpole submarine, letting you carry extra storage on deep dives without holding it in your hands. This makes resource-farming runs much more efficient. Read our full guide on how to build a Tadpole in Subnautica 2.

Build Base Storage as Soon as Possible

Your personal inventory is for active use on dives. Your base is where the real storage lives. As soon as you have the Habitat Builder, build lockers in your base so you can offload materials between runs and keep only what you need on you.

Two types of base lockers are available:

• Wall Lockers: Easy to craft and space-efficient. Good for organizing materials you access regularly.
• Floor Lockers: Offer more storage slots per unit than Wall Lockers. Better for bulk material storage.

Once you have a base with lockers set up, use the Portable Lockers you’ve found to ferry materials from your Lifepod to your main base in bulk, then offload into your organized storage system. This completely changes how efficient your gathering runs feel. For help getting started, see our guide on what to build in your base first and how to unlock the Habitat Builder.

Use Your Hotbar to Free Up Inventory Slots

Tools and consumable items can be slotted into your hotbar at the bottom of the screen. This effectively gives you 5 extra functional spaces that don’t eat into your main inventory grid.

Put regularly-used items like your water bottle, a snack, and a spare battery in hotbar slots. This keeps your main inventory free for materials. After claiming the Dexterity Biobed upgrade, you gain a sixth hotbar slot, which makes this even more flexible.

A good lean loadout for most dives:

• Hotbar: Water, food, spare battery, Air Bladder, key tool for the dive.
• Inventory: Leave as many slots empty as possible for collecting materials.
• Leave the Habitat Builder at base if you’re not building. Leave the Scanner at home if you’re on a pure gathering run.

Smart Inventory Habits That Save a Lot of Space

Don’t Break Down Metal Salvage Until You Need It

This is the most common inventory mistake in Subnautica 2. One piece of Metal Salvage takes up one slot. Breaking it down gives you four pieces of Titanium — which then take up four slots. Keep your Metal Salvage whole until the exact moment you need the Titanium for a recipe. You’re quadrupling your footprint otherwise.

Pin Your Active Blueprints

Right-click a recipe in the crafting menu to pin its required components to the top right of your screen. This shows you exactly what you need to grab, so you don’t pick up materials you don’t currently need. Targeted gathering is far more efficient than hoarding everything you see. See our guide on how to unlock blueprints and crafting recipes for more.

Split Your Trips by Purpose

Exploration runs and gathering runs are two different things. On exploration runs, travel light — take food, water, and tools, leave room for anything worth scanning. On gathering runs, empty your pockets first and focus on filling up with one target material. Don’t mix the two. This habit pays off faster than any other change you can make to your play style.

Only Carry What You’ll Actually Use

If you’re going on a gathering run, leave the Habitat Builder at home. If you’re scouting new terrain, don’t load up on heavy materials you found on the way. Take a spare battery, one snack, one water, and your relevant tool. Everything else is dead weight.

Don’t Panic After Dying

If you die with a full inventory, your items drop at the death site in a small yellow container. Your permanent inventory upgrades and base storage are untouched. Go back and recover your bag once you’ve restocked at base. Read our full guide on what happens when you die in Subnautica 2 so you always know what to do next.

Vehicle Storage — Tadpole Haul Chassis

Once you build the Tadpole, you can unlock the Haul Chassis upgrade. This structural attachment adds catamaran cargo pods to the vehicle, giving you built-in storage space on dives without needing to hold a Portable Locker in your hands. It also adds a second hardpoint and can carry up to three additional passengers in co-op.

For long resource-farming sessions in the mid-game, this is one of the most valuable upgrades in the game. The Haul Chassis blueprint is unlocked by scanning its fragments. Check our complete Tadpole building and upgrade guide for full details.

Inventory Upgrade Summary

• Default inventory: 20 slots + 5 hotbar spaces.
• After all 3 Endurance Biobeds: 29 slots.
• After Dexterity Biobed: 29 slots + 6 hotbar spaces.
• Portable Locker (carried): +15 temporary slots while held.
• Tadpole Haul Chassis: vehicle-side storage for materials during dives.
• Base lockers (Wall + Floor): unlimited base storage, no personal slot cost.

More Subnautica 2 Guides

• Subnautica 2 beginner tips and tricks
• Best early upgrades and progression path
• How to get Quartz
• Where to find Silver
• Where to find Copper
• How to get Sulfur
• How to get Fiber and Fibrous Pulp
• How to harvest large resource nodes
• How to get Necrolei Cysts and Strong Acid
• How to get Rubber from Lucifer Rotsac
• How to get an Acidic Raion Pouch
• How to build a Scanner Station
• Subnautica 2 multiplayer co-op guide
• Subnautica 2 release date, platforms, and price

Subnautica 2 is available now in Early Access on Steam and Xbox, including Xbox Game Pass.