Oxygen (O) is a gas that is needed by the player to survive. When diving, the player uses a reserve of Oxygen that diminishes over time. If the player runs out of Oxygen, the player's screen will fade to black, and they will have only a few seconds to get to air before the screen completely fades out and they die. 

The player's Oxygen reserve automatically replenishes whenever they comes back to the surface or enters a vehicle or a powered Seabase. Oxygen is produced within the Seabase, Seamoth and Cyclops naturally, as long as they have Energy. If they run out of power, no Oxygen will be produced. 

The HUD indicator for the player's Oxygen supply is located on the bottom left of the screen. The player has a base reserve of 45 units of Oxygen, which can be increased by 30 units by equipping a Standard O2 Tank or by up to 180 units with upgraded tanks.

The PDA will alert the player if they have less than 10 Oxygen remaining. The PDA will also alert the player when they have 30 Oxygen remaining, if they are diving far from the surface and don't have a tank equipped.[1] The PDA will not play these alerts in Hardcore Mode.

Depth is a factor that affects Oxygen consumption. When diving less than 100m the player will consume one unit per second; when diving between 100m and 200m three units are consumed per second; when diving deeper than 200m five units are consumed per second. This can be counteracted by equipping a Rebreather.

If a Cyclops catches fire, it will produce smoke, which will, over time, cause the player to run out of Oxygen and suffocate.

Future PlansEdit

  • In the future, indoor Flora will be able to produce Oxygen within a Seabase, allowing the player to breathe even if the power is depleted.[2]

Trivia Edit

  • The player can use the Console Command "oxygen" to have unlimited Oxygen.
  • If the player is depleted of Oxygen and gets to the surface when the screen is fading, different breathing responses will occur coming from the player.


  1. The alerts play when there are 10 and 30 units left. The first one simply says "Oxygen", but the second one says that there are "30 seconds of Oxygen remaining", but depending on the current depth, the player can deplete three or five units per second, so when the alert says there are "30 seconds of Oxygen remaining", there could be actually less than 10 seconds.