You need to find a new air tank and equip it from your inventory

In Sons of the Forest, your air tank runs out of oxygen when you spend time underwater or in caves with poor air. When the tank empties, you cannot breathe and will start taking damage. To change tanks, you first need to find a second tank somewhere in the game world, then open your inventory and equip the new one — the game will automatically swap it for your current tank.

The process takes a few seconds and you can do it while standing still or while moving. You do not need to be at a specific location or wait for a particular time of day. If you are underwater when your tank runs out, you will need to surface or find an air pocket before you can equip a new tank, since you cannot access your inventory while drowning.

Key Takeaways

  • Air tanks are found in caves, shipwrecks, and abandoned structures throughout the map, often near diving areas or in supply caches.
  • Open your inventory by pressing Tab (on PC) or the inventory button on your controller, then select the air tank and choose "equip" to swap it for your current one.
  • Your character can carry multiple air tanks at once, so you can pick up spares without dropping other items.
  • A full tank lasts roughly 2 to 3 minutes of continuous underwater breathing, depending on how deep you are diving.

Where to find air tanks in the game world

Air tanks spawn in specific locations tied to diving and exploration. The most reliable places are inside caves that have water sections — particularly the cave system on the western side of the map and the flooded caverns near the coast. You will also find tanks in shipwrecks, which are underwater structures you can spot from the shore or by swimming out into deeper water.

Supply caches and abandoned campsites sometimes contain air tanks as loot. These are usually marked by scattered supplies, tents, or storage containers. The game does not mark these locations on your map automatically, so exploration and checking caves thoroughly is the main way to build up a supply. Once you pick up a tank, it stays in your inventory until you use it or drop it intentionally.

How to equip a new tank from your inventory

Press Tab on PC to open your inventory menu. On console, use the inventory button (usually mapped to a shoulder button or the menu button depending on your controller). Your inventory will show all items you are carrying, organized by category. Air tanks appear in a section labeled "equipment" or "gear."

Highlight the air tank you want to use and select "equip" or press the confirm button. Your character will automatically remove the old tank and put on the new one. The swap takes about one second and you will see your oxygen meter reset to full. If you have multiple tanks, you can switch between them at any time, even in the middle of a dive — just surface or find an air pocket first if you are running low on oxygen.

Understanding oxygen drain and tank duration

Your oxygen depletes faster the deeper you dive. At shallow depths (near the surface), a full tank lasts around 3 minutes. At medium depths, you get roughly 2 to 2.5 minutes. At the deepest parts of the map, a tank may only last 1.5 to 2 minutes before you need to surface or switch tanks.

You can see your current oxygen level in the top left or bottom right of your screen (depending on your settings) as a blue bar or number. When it reaches zero, you will start taking damage and will drown within a few seconds if you do not reach air. Switching to a fresh tank before you hit zero is the safest approach, especially if you are exploring an unfamiliar area and do not know how far the nearest air pocket is.

What happens if you run out of tanks underwater

If your oxygen meter empties and you have no tanks left in your inventory, you will begin to drown. You take damage every second until you either reach the surface, find an air pocket inside a cave, or die. Drowning is one of the faster ways to lose health in the game, so it is worth carrying at least two tanks when you plan to do serious diving or cave exploration.

If you die underwater, you will respawn at your last shelter or base. Any tanks you were carrying will be lost, though you can return to the spot where you died and retrieve them if you act quickly. This is why building up a supply of spare tanks at your base is a good strategy — you can grab extras before heading out on a long expedition.

Tips for managing multiple air tanks

Carry at least two tanks whenever you plan to spend time underwater. One tank gets you down and exploring, and the second gives you a safety margin to get back to the surface or to an air pocket. If you are diving to a location you have never been before, bring three tanks so you have room for error.

Store extra tanks at your base in a storage container or on the ground near your shelter. This way you can grab fresh ones before each dive without having to search the map every time. Mark diving locations on your map (if the game allows) so you remember where you found tanks before and can return there if you need more. Some players also leave tanks at strategic points along diving routes so they can swap mid-dive without surfacing.

Frequently Asked Questions

Can I use an air tank without equipping it first?

No, you must equip the tank from your inventory for it to work. straightforward carrying a tank does not give you oxygen. Once equipped, it becomes your active air supply and the oxygen meter will show how much is left.

What if I equip a tank that is already partially used?

Partially used tanks work fine — they just have less oxygen remaining than a full tank. The meter will show whatever oxygen is left in that specific tank. You can refill tanks at certain base locations if the game includes a refill mechanic, or you can find new full tanks in the world.

Do I lose my old tank when I equip a new one?

No, your old tank goes back into your inventory as a separate item. You can carry multiple tanks at once and switch between them whenever you want. This means you can equip a fresh tank, use it, then equip the partially empty one later to finish using it.

Can I drop a tank and pick it up later?

Yes, you can drop any tank by opening your inventory, selecting it, and choosing "drop." The tank will appear on the ground at your feet. You can pick it up again later by walking over it or opening your inventory and selecting it from the ground items list.

Is there a tank capacity limit or do I run out of inventory space?

Air tanks take up inventory slots like any other item. If your inventory is full, you cannot pick up a new tank unless you drop something else first. Managing your inventory space is part of planning longer expeditions — bring only what you need so you have room for multiple tanks.