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Suunto EON Core User Guide 3.0

Dive modes

By default, Suunto EON Core has two dive modes: Air/Nitrox and Gauge (bottom timer). Select the appropriate mode for your dive under Dive settings » Mode.

Dive mode EON Core


Suunto EON Core shows all dive mode names in English. You can change dive mode names via Suunto app.


The default dive modes use prominent style. You can change the style and other settings, as well as create additional dive modes using the Suunto app.

In Suunto app you can create new or edit existing dive modes, modify screen layouts, change helium and multi-gas settings, and change dive type (OC/CC). You can activate CCR (closed circuit rebreather) dive support in Suunto app.

The decompression algorithm used in Suunto EON Core is Suunto Fused™ RGBM 2. For more information about the algorithm, see Decompression algorithm.

Air/Nitrox mode

By default, Air/Nitrox mode is for diving with regular air and diving with oxygen enriched gas mixtures.

Diving with nitrox gas mixture allows you to increase bottom times or reduce the risk of decompression illness. Suunto EON Core provides you with information to adjust your dive and stay within safe limits.

When diving with nitrox gas mixture, both the percentage of oxygen in your tank and the oxygen partial pressure limit must be entered into Suunto EON Core. This ensures correct nitrogen and oxygen calculations and the correct maximum operating depth (MOD), which is based on your entered values. The default oxygen percentage (O2%) setting is 21% (air) and oxygen partial pressure (pO2) setting is 1.6 bar (23 psi).


When diving with a nitrox gas mixture, Suunto recommends changing the partial pressure to 1.4 bar (20 psi).

Air/Nitrox mode has two views by default:

  • No deco

    airnitrox nodeco eon

  • Compass

    airnitrox compass eon

After customizing in Suunto app, two other views are available:

  • Tank Pressure - For more information on what is shown on the display, see Tank pressure .

    airnitrox tank pressure eon

  • Timer

    image:airnitrox timer eon


Air/Nitrox dive mode has one active gas by default. You can edit this gas in the device menu where O2 percentage and pO2 value can be changed. To enable diving with more than one gas, you need to activate multigas diving under Dive settings » Parameters » Multiple gases. After this step you are able to add further gases in the Gases menu. Gas settings can also be customized in Suunto app.

Gauge mode

Use Suunto EON Core as a bottom timer with Gauge mode.

The timer in the top right of the display shows dive time in minutes and seconds and can be activated and stopped by short pressing the upper button. Keep the upper button pressed to reset the timer.

Gauge mode is a bottom timer only. It does not use any decompression algorithm, thus it does not include decompression information or calculations.

Gauge mode has two views by default:

  • Timer

    Gauge timer eon

  • Compass

    Gauge compass eon

A third view is visible after customizing in Suunto app:

  • Tank Pressure - For more information on what is shown on the display, see Tank pressure .

    Gauge tank pressure eon


After diving in Gauge mode, decompression calculation is locked for 48 hours. If during this time you dive again in Air/Nitrox mode, the dive algorithm and the decompression calculation will not be available and Locked will be shown on the screen


Locked time is set back to 48 hours if you start a new dive while your device is locked.

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