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Dive computer reviews are perfectly organized and consist of fully researched information and ratings of Aeris, Cressi, Mares, Oceanic, Sherwood, Suunto, Tusa, and UWATEC/ScubaPro brands.  In Catalogue Section you may compare any models side-by-side and select dive computer according to your needs! Join thousands of happy customers!


Mares M2 - Simple to Use and Easy to Trust

Mares M2 - Simple to Use and Easy to Trust

Mares M2 is suitable for both beginners and recreational divers with the experience. 3 dive modes, 1 Nitrox mix, user replaceable 2 alkaline 1.5V batteries - what can be easier!

General Information
User Interface
Your Review



Mares M2 is not an air-integrated dive computer, and it is suitable for recreational and for the beginners as well. It is packed with all necessary functions, reliable and easy to use Nitrox computer. If you decide to go for this one, you may make a console with pressure gauge, and optional compass unit kit.

It is pretty straightforward dive computer and if you think that 1 Nitrox gas mix is enough for you and do not wish to pay higher price for more sophisticated stuff - just make a console and you will have everything you need to diversify your diving adventures!


Mares M2 Features Card

Copy this Mares M2 Features & Alarms Card for your Reference and Share with your friends and buddies!



Benefits of using Mares M2 dive computer

  • you will be able diving in all possible recreational scenarios - Air, Nitrox and Gauge modes cover all needs;
  • you will get very user-friendly and trustworthy dive computer;
  • you will have dive computer with big buttons that are easy to press even in thickest gloves;
  • you will be able diving down to 150 meters;
  • you will be able to save money by investing in Mares M2 dive computer;
  • you will be able to replace battery yourself easy;
  • you may build a console by adding SPG








User Interface
2 buttons
Dive Modes
Air, Nitrox, Gauge
Integrated Digital Compass
Mares-Wienke RGBM
Number of Gas Mixes
Air, 21% - 50%
1.2 - 1.6 ATA
Air Integration
Safety Stop (SS)
Deep Stop (DS)
Conservative Factor
Altitude adjustment
P0 - P3 (0 - more than 2400 meters)
Gas Switching
Dive Planner
12 - 48 meters
Logbook Capacity
50 most recent dives or 38 dive hours
Max Operational Depth
150 meters
Backlight duration
15 sec
Sampling Rate
20 sec
User Replaceable Battery
Battery 'hot swap'
PC Interface
2 years










This dive computer has 2 control buttons at the front face.

Display consists of two layouts - WIN 1 and WIN 2. You may swap between them any time to see any additional information.

Mares M2 has 1 Bar Graph - Ascent Rate Bar Graph. It has 5 segments and the last one with the message 'Slow'.







Mares M2 has Set mode subdivided into 5 submodes, and when you will easy access all of them, you may set following features.


Mares M2 Settings Card

Copy this Mares M2 Fine-Tuning Card for your Reference and Share with your friends and buddies!


To activate the backlight for about 15 seconds - press and release the right button. If you want it permanently - press and hold the right button for 2 seconds. To switch it off - press the right button again.







We will see what Mares M2 shows us on its different displays. Information displayed depends on which conditions you are in and what diving mode you have – whether you dive with Air, Nitrox, or Gauge, and No-Decompression or Decompression conditions.


Mares M2: Diving With Air & Nitrox

Dive computer has 2 layouts of display – WIN 1 and WIN 2. You may switch between them any time by pressing left button.


Mares M2 NO-DECO Card

Copy this Mares M2 No-Deco Diving Display Card for your Reference and Share with your friends and buddies!


Here I agree with other divers, that M2 is missing Nitrogen Loading Bar Graph. Dive computer displays No-Decompression Time Remaining in minutes, but it would be very nice to have some indication of the nitrogen loading ratio on display.

Upon reaching certain conditions, M2 may give you Safety Stop prompt or 1 minute Deep stop prompt with all related dive information displayed.

As all other dive computers, Mares M2 constantly monitors your ascent rate, and if your ascent is faster than allowable at certain depth – dive computer beeps and shows you bar graph with all segments in solid colour and the last segment with word ‘Slow’.

When you set this dive computer for Nitrox, it monitors dive time and depth, and calculates safety limits for oxygen exposure according to FO2 that you set during initial adjustments.

Computer manages diving with Nitrox the same way it does when we dove with Air. The only difference is M2 calculates and displays few more crucial parameters, which are typical for Nitrox dives. Those parameters are:

  • PO2 - alarm goes on if value exceeded the maximum value that you programmed in ‘Set Mode’;
  • Oxygen toxicity (%CNS) – alarm goes on if value exceeded 75%;
  • Maximum depth allowed for particular Nitrox gas mix


So, while diving with Nitrox, you will see few more parameters and icons displayed in addition to what you have on displays when diving with Air. And here they are:

  • Nitrox icon;
  • %CNS O2;
  • % O2 (FO2);
  • applicable icons – No-Decompression or Decompression icons


For Nitrox mode Mares M2 has two very important alarms:

  1. High PO2;
  2. High O2 (%CNS)


If you reach a certain depth that is greater than allowable for Nitrox gas mix you set up before - M2 will give an alarm until you will ascend to shallower depth where PO2 will return to acceptable limits.

High O2 alarm pops up if your oxygen toxicity level reaches 75%. At this moment you need to think seriously about terminating the dive!


Decompression mode starts when we exceed No-Decompression Limits (NDLs). When No-decompression time remains approximately 1 minute, instrument produces an alarm to notify you. According to this alarm you should ascent, and if you do not – Mares M2 switches to Decompression mode and all calculations will run as for ‘deco' dive from that moment.


Mares M2 DECO Card

Copy this Mares M2 Deco Diving Display Card for your Reference and Share with your friends and buddies!


If we missed Decompression stop by any reason and didn't return to the Stop depth displayed within 3 minutes - dive computer would activate Omitted Stop mode and for the repetitive dive it would function as a depth gauge only without performing nitrogen and oxygen calculations.


Mares M2: Diving In GAUGE Mode

Next dive mode is Gauge. In this mode Mares M2 works as a depth gauge and timer only without performing calculations for nitrogen and oxygen exposure.

It has 2 layouts of display (you may switch between them by pressing the left button) and following information is displayed:

  • current depth;
  • max depth reached during a dive;
  • Ascent Rate – on the Bar Graph and numerical representation in m/min or ft/min;
  • temperature


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When we get out of water, we may access following functions:

  1. Dive Planner - scrolling through No-Decompression Limits - this function allows us to see our bottom times for the next dive according to residual nitrogen and oxygen exposure that we had from previous dives (range of depths - 12 - 48 meters);
  2. Dive simulator – this function allows us to simulate dives to get familiar with Mares M2 and shows data like in real dive with the accordance of current residual nitrogen and oxygen from previous dives;
  3. Log Book – saves 50 dives on unit memory and allows you not only view your dive data, but also scroll through the dives and profile points; Logbook data is safe during battery replacement;
  4. PC interface – this function allows you to transfer data from Log Book to a PC and configure various parameters of M2 using PC keyboard. For this operation we need to buy optional infrared (IrDA) unit to make a communication between dive computer and PC and special software, of course.







Mares M2: What Divers Say


  • very user-friendly and trustworthy dive computer;
  • reliability and simplicity of use;
  • great price for Nitrox computer;
  • powerful backlight - easy to read display in pitch dark conditions;
  • big buttons - easy to press



  • no Nitrogen Loading Bar Graph;
  • no Personal Conservative Factor adjustment


This dive computer has been here for a while, but it still stay solid among its fellows! Mares M2, in spite of its simplicity, makes the job done! And that's what we all want!

If you go for Mares M2 - make a console. It will give you additional levels of freedom! And overall - it is a great dive instrument, especially from specs and price point of view!

If you are beginner or advanced recreational diver and you need dive computer that has all you need for diving in various conditions, day and night, if you want durability and reliability and want to save some money for your other dive gear – this dive computer is for you!


Mares M2 ConsoleMares M2 Console
Dive-Computer-Wizard Rating
golden star golden star golden star golden star snow star


These days it may take time to find new Mares M2, because of many new dive computers with greater capabilities came to our market with very competitive prices. And even we may say that time of Mares M2 came to the end, these dive computers will be remembered as our faultless and good dive buddies!



Add comment
Vitaliy, 21 December 2012 17:52
Good Old Buddy Served Me Faithfully For Many Years

I was very happy with my Mares M2 dive computer. I used it not only at perfect conditions and warm waters, but also in far north and muddy waters, and diving at high altitude. With its easy to read screen and convenient user interface I always had my dive data right away - when I needed it!

Strong backlight was at great help and fast battery replacement - nice addition to the rest of the functions. Even I upgraded it with Mares Nemo Wide - I still think that M2 was one of the best dive computers I've ever used!

Charley, 4 October 2011 17:00
Mares M2 RGBM - Good Value For Money

I've been diving with Mares M2 for more than 5 years already. I have it with SPG in a console.

I can confirm that this configuration is all that may need any recreational diver, as it's basic computer with nitrox functions. It is perfect for night diving and diving in cloudy waters, as it has strong backlight and big buttons, so I woudn't miss them even if I had thick gloves.

User interface and display readout are quite intuitive after I spent some time to master it, reading through user manual and playing with Mares M2.

Changing the batteries - the easiest process on earth!

There are many of newer dive computers came in recent years, but I still use my old and reliable buddy - won't exchange it for anything else!

Jake, 22 December 2010 17:00
Mares M2 - The Simplest Dive Computer I have ever used

Although M2 is an old buddy and now I dive with Mares Nemo Air, and for the last 5 years I tried different models including Suunto and Oceanic - I always say that Mares M2 is the simplest dive computer I've been diving with.

Very user-friendly interface, intuitive menus, one nitrox mix, big enough display and strong backlight. We did well as for recreational diving!

Replaceable battery by user - very helpful if I was at the boat - no need to go to service center and pay extra-bucks for this!

It perfectly managed all deco-stops by giving me all necessary dive data - always was easy to follow its recommendations.

I couldn't say anything negative about this scuba computer. I could always rely on it no matter what conditions of diving I had! Well invested money and time!

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