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Suunto HelO2 - Technical Diving Is Its Essence

Suunto HelO2 - Technical Diving Is Its Essence

Suunto HelO2 was made with technical diving in mind & it was the first true trimix instrument from Suunto dive computers! It allows experienced technical divers programming up to 8 various gas mixes with 8%-99% O2, 0%-92% He. Highly customizable instrument with wireless, max operational depth of 120m, unique Suunto Dive Planner (SDP).

General Information
User Interface
Your Review



Suunto HelO2 is a very different dive computer from all scuba dive computers described on this website. And the main difference - HelO2 is a true multigas dive computer, allowing experienced technical divers to program it for up to 8 various gas mixes with 8%-99% O2, 0%-92% He components.

If you are a technical diver - you may definitely consider this Suunto computer for your adventures regardless of its high price, because this instrument is well worth each cent you will invest! HelO2 is recommended dive computer for technical diving.


Suunto HelO2 Features Card

Copy this Suunto HelO2 Features & Alarms Card for your Reference and Share with your friends and buddies!



Benefits of using Suunto HelO2 dive computer

  • you will get true multigas dive computer dedicated purely to technical diving;
  • you will be able to stretch your diving skills to the limits by using Suunto HelO2 dive computer as your buddy!
  • you will have wireless air-integrated dive computer that calculates your real bottom time;
  • you will get intuitive and easy to set up and use instrument with excellent manual and user-friendly setup;
  • you will have dive computer packed with Dive Manager that allows you easily set gas mixes on PC and upload to the dive computer;
  • you will have dive computer with excellent DECO management;
  • you will pay very reasonable price for such advanced dive equipment!








User Interface
4 buttons
Dive Modes
Mixed Gas & Gauge
Suunto Technical RGBM
Number of Gas Mixes
8%-99% O2, 0%-92% He
0.5 - 1.6 bar
Air Integration
Safety Stop (SS)
Deep Stop (DS)
Conservative Factor
Altitude adjustment
A0/A1/A2 (range from 0 to 3000 meters)
Gas Switching
Dive Planner
9 - 45 meters
Logbook Capacity
80 hrs with 20 sec sampling rate
Max Operational Depth
120 meters
Backlight duration
ON/OFF/5/10/20/30/60 sec
Sampling Rate
10/20/30/60 sec
User Replaceable Battery
Data Retention or battery 'hot swap'
PC Interface
2 years










Suunto HelO2 has 4 control buttons on the user interface panel: MODE, SELECT, UP, DOWN.


Suunto HelO2 dive computer
Suunto HelO2 dive computer display and user interface


Dive computer has 2 bar graphs to assist us during diving:

  1. Tank Pressure Bar Graph (left side) – shows tank pressure if transmitter is installed and paired;
  2. Ascent Rate Bar Graph (right side)







Before diving we need to set up general parameters to customize our Suunto computer. First you need to adjust time settings, date, units, backlight, tones, etc.

One of the nicest features Suunto HelO2 has is Dive Planner software. It allows you to plan a dive on your PC with different gas mixes, dive profile, decompression schedule and then simulate the dive.
Also Dive Planner makes it easy to create recipes for gases and download them, PO2 settings and alarms to HelO2. You may even download from dive computer to PC dive data and compared real dive values with those you planned before.


After setting general parameters we are ready to enter values for diving in Mixed Gas Mode. You may use Dive Planner for this and later download your data to HelO2 or enter manually straight to dive computer.

At this stage you need to set number of gases, and other parameters listed below:

  • FO2%;
  • He %;
  • Depth alarm – OFF, or in range 3 – 120 meters;
  • Dive Time alarm – 1 – 999 minutes;
  • Personal Conservative Factor - P-2/P-1/P0/P1/P2;
  • Altitude programs – A0/A1/A2 in range 0 – 3000 meters;
  • sample rate – 20 seconds factory default, but you may adjust it for 10/20/30/60 seconds;
  • Tank Pressure alarm – ON/OFF or in range 10 – 200 bar;
  • tank pressure – ON/OFF;
  • units;
  • HP (high pressure) code for wireless transmitter


Interesting thing about Personal Conservative Factor setting – this Suunto dive computer allows us to set negative values: P-2 and P-1. These two values must be entered only very experienced and physically fit technical divers, because it will make dive computer more liberal and increase possibility of Decompression Sickness (DCS).







Suunto HelO2: Diving In Mixed Gas Mode

Suunto HelO2 activates Dive Mode automatically after it senses depth greater than 1.2 meters.


Suunto HelO2 NO-DECO Card

Copy this Suunto HelO2 NO-DECO Card for your Reference and Share with your friends and buddies!


Suunto HelO2, as well, as Suunto D9, D6 and other dive computers from Suunto, has a function BOOKMARK that allows making bookmarks at certain diving profiles to save them and later download to PC for viewing and examining.

During No-Decompression dive you may have Safety Stops (Recommended and Mandatory) and Deep Stops remainders. Stop depths and times, and all applicable icons will be displayed to assist you on your way up.

This Suunto computer will surely give us Fast Ascent alarm if we exceed allowable maximum at certain depth. In this case we will see blinking Ascent Rate Bar Graph and backlight goes on with the audio alarm.


After you found yourself at certain depths when it is allowed to change gas mix – Suunto HelO2 will prompt you to do so. It is really easy operation – just use UP/DOWN buttons to find your desirable mix and select it, using SELECT button – easy as it is!

Little note here – if you want to swap to a gas mix whose PO2 value was exceeded – dive computer would not allow you to do this, and you would get an alarm instead!


If you exceed your No-Decompression Limits (NDLs) time and depth – Suunto HelO2 switches to Decompression mode. All data that you will get now is related to this mode.

This dive computer has Continuous Decompression feature that allows us to perform decompression within the certain range of depths, so called Decompression range. It starts from the ‘floor’ (deepest depth where deco stop time won’t increase) to the ‘ceiling’ (shallowest depth) and decompression is done between them.

Suunto HelO2 (as all Suunto dive computers) perfectly manages all Deco stops by showing you Ceiling depth, range of the ceiling zone, Total Ascent Time (TAT), indicators for correct ceiling zone and related icons and notations.

Correct decompression must be done within recommended ceiling zone, but not shallower. Sometimes, when waters are rough, you may miss correct ceiling. In this case HelO2 will give continuous audio signal with DOWN Arrow flashing and message ‘Error’.
It means that you have about 3 minutes to return to the exact Deco Stop depth or slightly below.

If you still violate decompression stop depth – Suunto dive computer locks to Error State and works as a depth gauge and timer only. In this case you should not dive for the next 48 hours.


Suunto HelO2: Diving In GAUGE Mode

When you select Gauge Mode – this Suunto dive computer will operate as a depth gauge and timer only. It won’t perform any calculations for No-Decompression depths and time limits. So, it is entirely your responsibility to make it safe to bottom and all the way up!

Display is very easy one:

  • current depth;
  • max depth reached during a dive;
  • bookmark notation (if you create any);
  • Timer (SET/RESET);
  • Elapsed Dive Time (EDT)







When you resurface and Suunto HelO2 dive computer senses depth shallower than 1.2 meters, the DIVING display will be replaced with SURFACE display. Below you may see information summary from main and alternative displays:

  • max depth;
  • dive time;
  • time;
  • temperature;
  • Surface Time;
  • No-Fly Time;
  • O2 %;
  • He %;
  • PO2;
  • OLF


Last 4 values will be displayed if you dove with mixed gases.


PLAN mode is one of four operational modes of this dive computer and you may access it on surface.
PLAN (PLANnodec) mode allows you to explore available No-Decompression times and depths, according to residual nitrogen loading from previous dives, if you have any. This function doesn’t have full features of Dive Planner PC software to plan technical dives, but it allows us to plan short subsequent recreational dives.

You need to know that Plan Mode calculates No-Deco times only for Mix 1. Even if you set other mixes – they won’t do any effect on calculations.


MEMORY mode has two useful functions:

  1. MEMLogbook – memory capacity approximately 80 hours with 20 second sampling interval;
  2. MEMHistory – it is a summary of all your dives

MEMLogbook is a very extensive feature. It has 3 pages with related information of each dive and it’s very detailed. Number of hours really depends on sampling rate that you set up initially.

MEMHistory records and stores a dive history for up to 999 dives. It displays data about deepest depth reached, total dive hours and total number of dives.

Suunto HelO2 works perfectly together with Suunto Dive Planner PC software

You will use this thing to create your plans for future dives. When you input max depths, bottom times, and desirable gas mixes for descent, bottom, and ascent – Dive Planner will calculate right timing for gas changing, decompression depths and decompression schedule. By the end, Planner will calculate gas volume that is required to complete the dive safely.
After this, you need to upload gas mixes, settings and alarms to HelO2 and if some fine-tuning required – you may easily do it manually from the dive computer interface.

In contrast to Suunto Dive Planner, Suunto Dive Manager (SDM) apparently is optional software. So you really need to have it to extend flexibility of using Suunto HelO2 and Dive Planner all together!

Dive Manager gives you possibility to download data from dive computer to your PC, then organize it, view and examine, transfer dive profiles to Dive Planner and print copies of dive profiles as well.







Suunto HelO2: What Divers Say


  • true multigas dive computer, recommended dive computer for technical diving;
  • wireless air-integration;
  • Personal Conservative Factor adjustment with negative values - gives you longer bottom time;
  • Dive Manager – very convenient function;
  • excellent manual;
  • intuitive and easy to set up and use;
  • user replaceable battery;
  • very reasonable price for such advanced dive equipment



  • only one transmitter supported;
  • changing mixes takes longer time;
  • smaller numbers may be difficult to see under certain conditions


As I said at the very beginning – Suunto HelO2 is a very sophisticated dive computer designed for technical divers only. It allows us to set up to 8 different gas mixes to diversify and stretch to greater limits our diving experiences and really grow into this amazing Suunto computer!

And by using it with Dive Planner and Dive Manager you will have perfect team for designing your next dive whether into the deep caves or wrecks.

It has all required features to perform decompression correctly and bring you all the way up safely - intuitive display layout, loud alarms, easy readable dive data.


Suunto HelO2 dive computerSuunto HelO2
Dive-Computer-Wizard Rating
golden star golden star golden star golden star golden star


If you are a technical diver and need dive equipment that will make you more flexible and comfortable in your deep adventures – you won’t go wrong with Suunto HelO2. Technical diving is an essence of this perfect Suunto dive computer!



Add comment
Anderson, 11 November 2013 07:46
Perfect Setup For Technical Divers

I'm diving with technical mixes for more than 10 years and the last few years Suunto HelO2 is my great buddy! It is very convenient with its Dive Planner and Manager where I may set mixes and upload them to dive computer. Dive computer has all possible functions that tech diver might need.

Setting gas mixes and swap them during a dive - is an easy procedure!

But I think it lacks more wireless transmitters support. I could pair only one TMT for my primary gas mix. User battery replacement option is great option as well.

Now it's being sold under USD1000 with transmitter and PC interface cable, isn't it great! I recommend Suunto HelO2 to any tech-diver!

Laurence, 20 October 2012 15:42
Comfortable And Solid Technical Diving With Suunto HelO2

I bought Suunto HelO2 not long time ago and still exploring its functions. I haven't used it for all 8 mixes, yet. But may say that it is very sophisticated computer for technical diving. I found a unit to grow into, as I want to go into the tech-diving.

I used it with 3 gas mixes and all settings were done quite easy by using special software and then uploading settings to HelO2 from my PC.

This dive computer needs to be learnt properly and user operating manual is a great help. Display is easy to read at depths and night dives. Wireless works fine, and I need to try hard to lose it.

I highly recommend Suunto HelO2 to technical divers who prefer wrist watch style dive computers.

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