Dive Computer Expert Reviews
Saving Your Precious Time And Finding The Best Dive Computer For You

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!


Suunto D4 - Ideal Recreational Dive Computer And Fashionable Wrist Watch

Suunto D4 - Ideal Recreational Dive Computer And Fashionable Wrist Watch

Suunto D4 is perfectly suitable for the beginners, recreational divers, and guys who became involved with freediving activities. Dive computer offers standalone digital watch, highly customizable functionality, 3 dive modes, 1 Nitrox mix, large Logbook capacity and Continuous Decompression.

General Information
User Interface
Your Review



Suunto D4 dive computer may be considered as a simplified version of well-known Suunto D6 and Suunto D9. It is perfectly suitable for the beginners, recreational divers and guys who became involved in freediving activity.

When we compare Suunto D4 with Suunto D6 – it is easy to see the differences right away! Below I made a list some of them:

  • D4 has a dedicated Free Dive Mode – D6 doesn’t have it, but has a Gauge Mode instead that can be used for freediving;
  • D4 has only 1 Nitrox gas mix – D6 has 2 Nitrox gas mixes;
  • D4, obviously, doesn’t have gas switching function;
  • D4 doesn’t have digital compass;
  • D4 has different display layout because of non-existent dual gas mix features mentioned above


Suunto D4 Features Card

Copy this Suunto D4 Features & Alarms Card for your Reference and Share with your friends and buddies!



Benefits of using Suunto D4 dive computer

  • you will learn quickly this dive computer thanks to its easy to follow user manuals and friendly interface;
  • you will get dive computer that is perfect for recreational diving;
  • you will have dive computer that covers all aspects of recreational and freediving;
  • you will have instrument with perfect DECO management;
  • you will have instrument that may be used not only as a dive computer, but also a elegant standalone wrist watch;
  • you will be able to customize Suunto D4 dive computer in deep level to suit your particular needs








User Interface
4 buttons
Dive Modes
Air, Nitrox, Gauge, FREEdive
Standalone Digital Watch
Suunto RGBM
Number of Gas Mixes
Air, 21% - 50%
0.5 - 1.6 bar
RGBM Attenuation
Safety Stop (SS)
Deep Stop (DS)
Conservative Factor
Altitude adjustment
A0/A1/A2 (range from 0 to 3000 meters)
Dive Planner
9 - 45 meters
Logbook Capacity
80 hrs with 20 sec sampling
Max Operational Depth
100 meters
Backlight duration
OFF/5/10/20/30/60 sec
Sampling Rate
Air/Nitrox - 1/10/20/30/60 sec; FREEdive - 1/2/5 sec
User Replaceable Battery
Data Retention or battery 'hot swap'
PC Interface
2 years










Suunto D4 dive computer has 4 control buttons on the interactive control console: MODE, SELECT, UP, DOWN.

User interface is very friendly and it didn’t take too much time to learn all buttons combinations.

You will enjoy learning this instrument and growing with it as a diver, because everything is logical and intuitive, no boring stuff!

It has only one bar graph, as well as D6 – Ascent Rate indicator, located on the right side of the display layout.







One of the main operational modes of this Suunto computer is Time Mode. It means that D4 is a fully functional digital watch. So, we will start setting up our wrist watch parameters. Settings are similar to Suunto D9 and D6 dive computers. Those parameters are listed below:

  • daily alarm;
  • time;
  • date;
  • dual time (alternative time – can be your travel destination time zone);
  • units;
  • backlight duration - 5/10/20/30/60 seconds;
  • tone – ON/OFF;
  • Stopwatch

Suunto D4 doesn’t have integrated digital compass in comparison to Suunto D6 and D9.

This dive computer has 3 dive modes: Air, Nitrox, and Freedive. When you will set parameters before diving – you may access only those parameters, which belong to certain mode. For example, you couldn’t access FO2 settings if you selected Freedive Mode. Some of parameters are shared between all 3 dive modes, like for instance Depth and Dive Time alarms and some others.

Ok, let’s continue setting up our dive computer! Parameters that are available for customization I listed below:

  • Depth alarm – factory preset to 30 meters; user adjustable with the range from 3 – 100 meters;
  • Dive Time alarm – range 1 – 99 minutes;
  • Depth Notify alarm (Freedive mode) – alarm at certain depth;
  • FO2 – 21% - 50%;
  • PO2 – 0.5 – 1.6 bar;
  • Personal Conservative Factor – P0/P1/P2 (to make dive computer more conservative);
  • Altitude program – A0/A1/A2;
  • Surface Time Notify alarm (Freedive mode) – alarm goes on when time interval between your previous dive and next dive elapsed;
  • Sample Rate for profiling - Air and Nitrox Modes – 20 seconds default; user adjustable for 1/10/20/30/60 seconds;
  • Sample Rate for profiling: Freedive Mode – 1 second default; user adjustable for 1/2/5 seconds;
  • Deep Stops - ON/OFF and stop length can be set for 1 or 2 minutes;
  • RGBM attenuation (for experienced divers) - although I’ve heard that even with RGBM attenuation setting to 50% Suunto D4 was still quite conservative







If you accidentally didn’t disable Dive mode by setting it to OFF – Suunto D4 goes to Dive mode automatically when it senses depth more than 1.2 meters. But it is better if you activate desired Dive mode before diving in order for dive computer to do pre-checks, like Altitude and Personal Conservative Factor settings, FO2 and PO2, battery status and few others.


Suunto D4: Diving With Air & Nitrox

Suunto D4 NO-DECO Card

Copy this Suunto D4 NO-DECO Card for your Reference and Share with your friends and buddies!


If you want to make a Bookmark for further viewing and downloading to PC – just press SELECT button and data will be saved in dive computer memory.

During No-Decompression dive you may have Safety Stops and Deep Stops remainders, depending on conditions you are in. Stop depths and times, and all applicable icons will be displayed to help you to manage those situations.

You may miss Recommended Safety Stop, but you have to complete Mandatory Safety Stop.

Mandatory Safety Stop is activated when you ascend faster than allowable maximum. And to prevent microbubbles developing RGBM algorithm gives you a prompt for stop. If you violated and did not comply with it – you would have shorter No-Decompression Times for next dive or longer surface time between this and subsequent dive.


If you want to set Suunto D4 dive computer for Nitrox dive – it gives you access to specific parameters, like actually enabling Nitrox Mode and FO2 and PO2 settings. Suunto D4 allows us to dive with one nitrox mix with FO2 21% - 50% (compare to Suunto D6 has 2 nitrox gas mixes with FO2 21% - 99%) and you may set PO2 from 0.5 bar to 1.6 bar

When you set up all values related to nitrox – D4 calculates maximum operating depth (MOD) according to PO2 and FO2 numbers. And if you exceeded PO2 that you set before - dive computer will give you an alarm. In this case you need to ascend safely above the PO2 MOD if you want that alarm to disappear!

During Nitrox dive you will get data similar to air dive, but in addition D4 displays information related to Nitrox Mode:

  • FO2 value;
  • PO2 value;
  • OLF – oxygen limit fraction (oxygen toxicity level)


If you exceeded No-Decompression Limits (NDLs) – Suunto D4 scuba dive computer would activate Decompression mode. All data that you will get after that is related to Decompression mode. During decompression you will be prompted to complete one or few decompression stops at a range of depths.

This Suunto computer (as well as other Suunto dive computers) 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. This feature is similar to Suunto D6 and Suunto D9 dive computers.

Suunto D4 manages decompression precisely by displaying following data:

  • Ascent Time in minutes (total time to surface, including time to reach the correct ceiling, time to stop at the ceiling, Mandatory Safety Stop (if any), time to surface after ceiling);
  • Ceiling depth and correct ceiling range;
  • Elapsed Dive Time (EDT);
  • max depth reached during a dive;
  • guiding arrows (for your correct ceiling depth)


All process of decompression is the same as in Suunto D6 and Suunto D9 dive computers – and it’s obvious! The same algorithm – the same procedure!

If you, by some reason, ascend above the correct decompression ceiling, D4 will give you an audio alarm with corresponding icons (DOWN Arrow), your current depth and ceiling depth values, and Error mark on top of all of that. It means that you have only 3 minutes to correct you position and go to exact ceiling depth displayed or below the ceiling.

If you violate the decompression totally – D4 will activate permanent Error Mode and will work as a depth gauge and timer only. You must not dive for at least 48 hours then!


Suunto D4: FREEdiving

Suunto D4 has function that can make happy guys who go freediving – dedicated Freedive Mode. If you freedive – D4 won’t calculate your No-Decompression limits and it won’t control your ascent rate.

Suunto D4 dive computer has 2 specific alarms only for freediving – one of them is Depth Notify alarm and another is Surface Time Notify alarm:

  1. Depth Notify alarm goes on when you reached certain depth that you set before diving.
  2. Surface Time Notify alarm reminds you when time on surface between you previous dive and next dive elapsed


In Freedive Mode, this Suunto computer displays following information:

  • total time of dive;
  • max depth reached;
  • current depth;
  • applicable notations


Freediving Mode has function, called Day History. After diving you may access this history and view following information:

  • average depth of all dives that day;
  • time and deepest depth reached during a day;
  • longest dive;
  • total number of dives and total dive time during a day


Next day if you start new dive in Freedive Mode – it will reset all day history and start all from the beginning.

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Now it is surface time. You just came out of water, got relaxed somewhere under the shade in your ocean boat, and had time to have a look on your dive logbook or plan your next diving activities. And Suunto D4 has everything to assist you to complete this task!

On surface you may access Memory Mode. It is the third operational mode of this Suunto dive computer and this mode and its sub-modes are similar to Suunto D6.

This mode has 3 sub-modes:

  1. MEMplan;
  2. MEMlogbook;
  3. MEMhistory


Below I gave brief descriptions each of these sub-modes.

MEMplan allows you to see your next No-Decompression times for particular depths for your next dive, taking into consideration any residual nitrogen you may have from previous dives.
This function is exceptional value for planning repetitive dives.

MEMlogbook stores in memory logs, bookmarks and profiles of approximately 80 hours of dives and its capacity depends on sampling rate that you set. Sampling rate is factory preset for 20 seconds for profiling, but you may set it for 1/10/20/30/60 seconds for Air and Nitrox Modes and 1/2/5 seconds for Freediving Mode.

MEMhistory has two sub-modes:

  1. Scuba History - records and stores a dive history for up to 999 dives and 999 diving hours of diving with Air and Nitrox;
  2. Free Dive History – stores maximum of 999 dives and 99 diving hours and 59 minutes. It displays deepest and longest dives, total dive time and total number of freedives.


To interface Suunto D4 dive computer with your PC - Suunto offers optional software - Suunto Dive Manager (SDM). It will allow you to download dive data to PC, organize it, plan subsequent dives, view and print your diving profiles. You may visit Suunto website from time to time to check for newest version of this program.







Suunto D4: What Divers Say


  • reliability and quality;
  • simple to use Suunto computer and read dive data;
  • very nice graphic dive profile display;
  • perfect for the recreational diver;
  • easy to navigate through the menus



  • no user replaceable battery option


Suunto D4 is a perfect for either backup or main dive computer for recreational diving whether you are a beginner or experienced diver.

Easy and quick to learn and easy to use dive equipment – if you have it tomorrow – you will be ready to dive in one day!

Only related data and nothing uselessness – that’s the main backbone of this rigid and friendly at the same time dive computer!

I think, only one big inconvenience of D4 - no user replaceable battery. It may bring owner some discomfort, especially if he/she somewhere onboard.


Suunto D4 dive computerSuunto D4
Dive-Computer-Wizard Rating
golden star golden star golden star golden star half star


If you want to have not only fashionable wrist watch for everyday life, but also reliable dive computer in one small package and not pay for this fortune of money – go for Suunto D4. You will never be disappointed with this Suunto dive computer!



Add comment
Max, 8 November 2013 04:06
Dive Watch Computer For Everyday Use

I was looking for combination of dive computer and wrist watch for everyday wear and Suunto D4 came to selection. I still use it, nevertheless it had its air-integrated version. Suunto D4 has all I need as a recreational and freediver, and standalone wrist watch has all essential functions of normal wrist watch, that we may find around.

Couldn't find any downsides of D4, except no user change battery option. Every 1.5 years I need to send it to retailer to swap battery and pay extra money. This is a bit frustrating, especially if I count those procedures for few times - I could buy another dive computer!

TaniaK, 4 September 2013 10:45
Suunto D4 - User Friendly & Made To Enjoy Diving

I've been diving with Suunto D4 for quite a while and retired this dive computer this year in favor of Suunto D6i ! But I still think that D4 is one of the best no air-integrated dive computer for recreational and freedivers around!

It is very user friendly with good written documentation. Display has all crucial info I needed and nothing else at any time. I learnt interface very quick, it was much easier than similar Oceanic models.

Only one complaint - it's NO user replaceable battery option, so beware of that!

Lloyd, 18 August 2012 16:35
Stylish Suunto D4 And Multifunctional Dive Computer

Suunto D4 is an awesome dive computer. It does the job really well. It shows on a main display what I really need to know at the certain moment and if I need extra-data, I can call alternative screens.

Owner manual is as simple as you may get. And it is very easy to use and operate.

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