Suunto D4i and D4i Novo Dive Computer Review

suunto d4i novo dive computer review

The Suunto D4i Novo is the updated version of the Suunto D4i. There are only 3 changes to note, and all of them are minor. Both dive watches are solid products that provide Air, Nitrox, and even a full-fledged freediving mode. If you are a scuba diver who also dabbles in a bit of freediving or vice versa, then this versatile and stylish dive watch should be right up your alley.

In this review, we will cover both the Suunto D4i and D4i Novo dive watches since they are so similar beyond some cosmetic changes. We will also compare these dive computers to dive watches with similar functionality and price to see which ones are worth your money.

What are the Differences Between the D4i and D4i Novo?

Suunto likes to update their older dive computers and rebrand them as “Novo”, such as the case with the Zoop Novo and Vyper Novo. In some cases, additional functionality is added which may sway one’s decision to get the latest version, and leave owners of the older model jealous.

In this case, owners of the original model can rest assured; the internal components and functionality of the D4i and D4i Novo have not changed. What did change, however, is its appearance. Cosmetically, the buttons and screen are slightly different. Where the D4i had plastic buttons, the D4i Novo now has metal buttons.

Additionally, Suunto has changed the elastomer band on the D4i to a silicone band on the Novo. Silicone is smoother than elastomer and feels notably more comfortable to wear for long periods of time.

Next, the D4i Novo’s case is almost imperceptibly heavier by 0.25oz (7 grams) than the D4i. Both are lightweight, compact, and easy to bring with you while travelling.

Furthermore, the USB cable that is required to transfer the dive log from the dive watch to a computer comes included when you purchase a D4i Novo. If you purchase a D4i, then you will have to buy the USB cable separately. With that said, the D4i Novo is 25% more expensive, so there isn’t much savings to be had, if any.

Also, the Novo comes in more colors, if you want to color match with your other Scuba equipment.

As you can see, these changes are mostly cosmetic and do not change the core functionality of the dive watch. If you already own the D4i, there’s not much point in “upgrading” to a Novo.

Technical Specifications

  • Four operating modes: Time, Dive, Dive Planning, and Memory.
  • Three dive modes: Air/Nitrox, Gauge, and Freediving.
  • Standalone digital watch.
  • Dot matrix display is easy to read.
  • Supports air integration for remaining air time and current cylinder pressure.
  • Compact and lightweight watch-style design.
  • Runs on the Suunto RGBM decompression model.
  • Has audible and visual alarms.
  • ppO2 of 1.2 to 1.6 bar.
  • Air/Nitrox sampling rate of 1/10/20/30/60 seconds.
  • Freedive mode sampling rate of 1/2/5 seconds.
  • Adjustable backlight duration of ON/OFF/5/10/20/30/60 seconds.
  • Logbook capacity: 80 hours at a 20 second sampling rate and can be viewed in great detail when downloaded to your computer.
  • Tracks different data for scuba diving and freediving.
  • Adjustable altitude and conservatism settings.
  • Alarm clock functions.


We like the trend of dive computer designs becoming more watch-like, and often coming with watch functions so you can use it like a wristwatch. The days where divers have to use bulky computers that look like they were made for astronauts are slowly coming to an end.

The D4i is a watch style dive computer that measures 1.91in (48.6mm) in diameter, is 0.63in (16mm) thick, and weighs only 3oz (85g) so it can sit comfortably on your wrist. With modern divers looking to slim down their dive equipment as much as possible, this sleek dive watch can be a nice addition. It’s also nice to have a dive computer that can be used outside of the water and not look out of place.


Thanks to the dot matrix display, the D4i and D4i Novo has a clear and bright screen that has issues being read underwater and even in low-visibility conditions. The electroluminescent backlight means that it will glow in the dark so you can always see what’s going on.

Normally a smaller design compromises on the screen’s visibility or makes it hard to navigate the interface, but that isn’t the case here. The four navigational buttons (MODE, SELECT, UP, DOWN) are easy to use and it won’t take very long for you to navigate through the menus like a pro.

Dive Modes

Air and Nitrox Mode

The D4i and D4i Novo dive computers support diving with only one gas: standard air or Nitrox, with 21% to 50% oxygen percentage and a ppO2 limit between 1.2 and 1.6 bar.

While in air/nitrox mode, there will be reminders for Recommended and Mandatory Safety Stops, and you can also set DEEP Stop to on or off. These stops are activated once you dive deeper than 10 meters.

Missing a Recommended Safety Stop will not penalize you by decreasing bottom time or increasing surface intervals, however Mandatory Safety Stops should be followed accordingly. Each safety stop reminder also triggers an audible warning so it is easy to notice it.

When diving at altitude, you can manually adjust the altitude settings to fall in range of the correct values. The three levels are A0-A2, which cover from 0 meters (sea level) to 3,000m (~9,800ft).

If you exceed your no-decompression limits (NDLs) then the D4i will automatically switch to Decompression mode. While active, you will be prompted to complete at least one or more decompression stops before reaching the surface.

The D4i, along with other Suunto dive computers, has a unique Continuous Decompression feature. Essentially, the way it works is by telling you the rate at which you can ascend so that you can very slowly make your way up without needing to fully stop.

You will still be decompressing, but it feels like you’re making more progress since you can always be moving, albeit slowly. Just follow the dive computer’s instructions completely to decompress without issue.

If you ascend too quickly or ascend above the decompression ceiling, the D4i will sound an audio alarm and display a DOWN Arrow, as well as current depth, ceiling depth values, and an Error symbol. When this occurs, divers should move down to the recommended ceiling depth or lower within three minutes and wait out the safety stop.

Should divers ignore this warning, whether purposely or accidentally, the D4i will switch to Error mode. This mode limits the dive computer to only provide a depth gauge and timer while locking out all other functionality for 48 hours.

Lastly, the D4i has many adjustable settings including the current altitude and conservatism level. The current values are displayed on the startup screen after entering DIVE mode. Change the conservatism from P0 (default) to P1 or P2 (the most conservative setting) to make the dive safer, if you prefer.

Freedive Mode

Suunto have really catered to the freediving community this time around by including a dedicated freediving mode (labeled as ‘FREE’ in the menus). With that said, watches with a freediving mode still aren’t the norm, so having it is a nice bonus.

Since freedivers move through the water a lot quicker than a scuba diver (being air restricted does tend to do that to people), the sampling rate of 3 times per second while in freediving mode allows the D4i and Novo to keep up with the quick pace. It can also detect the start of a dive very quickly.

Furthermore, the D4i’s brand new surface alarm, along with its standard multi-depth and time settings allows freedivers to focus on their dive without needing to look at their dive computer for information. It is difficult to set new depth records if you’re splitting your attention 50/50 with your dive computer and the dive itself, so the alarms are really helpful in that regard.

Alarms and Warnings

The Suunto D4i has numerous audible and visual alarms which can be customized to suit your preferences, such as maximum depth and ascent rate warnings. In FREE (freediving) mode, you can customize the depth notification alarm to activate once a certain depth has been reached.

When diving with a transmitter, the D4i has low air pressure warnings in the form of a blinking pressure display, as well as two audible double beeps once the remaining air hits 50 bar (700 PSI). When the cylinder pressure reaches the user-selected alarm pressure, as well as when the remaining air time is depleted, the D4i will emit two double beeps as a warning.

Your ascent rate is represented by the vertical bar located on the right-hand side of the display. Should the maximum allowable ascent rate be exceeded, the lower section of the bar will begin to blink, while the top section remains solid. Failing to adhere to the ascent rate or any safety stops will cause the device to switch to Gauge mode for 48 hours, essentially preventing you from diving.

Wireless Air Integration Support

The D4i supports wireless air integration using the Suunto Transmitter. It is easy to install in a regulator’s first-stage HP port. Once installed, you can get a clear reading of your remaining air time (RAT), which takes into account your depth, tank pressure, and decompression status to calculate how much longer you can safely stay underwater.

Furthermore, when using the wireless transmitter, the D4i will show the remaining gas pressure from 0 to 350 bar (0 to 5000 PSI). This advanced technology ensures that all of the crucial information can be read at a glance from your wrist, so that the rest of your attention is on your dive.

Decompression Model

The D4i and D4i Novo use Suunto’s RGBM algorithm, which is aimed at recreational divers. It takes into account your unique diving behavior and makes adjustments based on your dive profile.

The RGBM algorithm takes into account repetitive diving, continuous multi-day diving, ascent rate violations, and reverse profiles, all of which can cause nitrogen to accumulate in the body. To gather data, the D4i uses a depth sensor and timer to calculate approximately how much gas is being absorbed and released during the dive. The data is then calculated to produce your no-decompression limit (NDL).

In other words, the Suunto RGBM algorithm creates a model of what is occurring to your body during the dive based on the data it is tracking about you. Divers may find that the Suunto RGBM algorithm is more conservative than other models, leading to less bottom time. Some divers complain that they have to surface quicker than their buddies with more liberal algorithms.

For instance, the Pelagic DSAT algorithm found in Oceanic dive computers is more liberal than the RGBM model found in Suunto dive computers due to its generous NDLs. That isn’t to say that liberal algorithms are dangerous and that most conservative computers are better.

The end result is simply that Suunto computers tend to reach the NDL faster than dive computers from other brands. Suunto is simply putting safety first, and that is not necessarily a bad thing in a hobby with as many risks as diving.

Unfortunately there isn’t an option to make the RGBm algorithm more liberal, only more conservative, so if you aren’t satisfied with the default conservatism levels then you will not enjoy using this device.

For an idea of how conservative the algorithm is, here are some actual numbers. The RGBM model has mandatory safety stops in a 3-6m (10-20ft) depth zone on all dives that exceed 10m (30ft). Next, the maximum allowable ascent rate is 10m/33ft per minute. It also restricts deep spike diving, multi-day activity, and reverse profiles.

Dive Log and Connectivity

After you have finished your diving trip, you can view all of the dives you have done recently using the dive log. The D4i is capable of recording the last 140 hours (~100 dives) of dive data in its logbook memory. With transmitter data included, the capacity is lowered to 35 hours. You can then transfer this data to your PC or Mac using the USB cable.

You can also set bookmarks to your dive log so that specific moments can be viewed when looking through the logbook. Each bookmark contains the exact depth, time, heading, water temperature, and tank pressure the moment the bookmark was created.

When you purchase a D4i Novo, the USB cable is already included in the box. If you purchase the standard D4i, you have to purchase the cable separately. Use the cable to interface the dive computer and your computer, and then use the Suunto Movescount portal to transfer the data.

View your dive logs in great detail and even add photos and videos of your dives to the logbooks and share it across social media so friends and family can see your scuba adventures.

Lastly, the portal lets you plan for future dives based on past dive data. Dive activity from the log can be displayed in charts to help you analyze it in-depth. Using this knowledge, you can better adjust the settings of the device, such as when alarms should trigger, to prepare you for future dives.

Caring for Your Device


Dive computers are expensive and sophisticated devices and proper care should be given to ensure that they last for years. These computers are designed to endure a certain amount of punishment that comes naturally from scuba diving. With that said, you should still endeavor to handle it carefully and to wash it thoroughly in fresh water after each diving session.

Keep your dive computer away from direct sunlight, or to wash it using harsh chemicals. Keep it in its case so that other equipment doesn’t scratch it in the bag. We recommend using a mild soap when rinsing it, and to dry with a chamois or soft cloth.

Furthermore, do not attempt to open up the Suunto D4i unless you have experience with taking apart dive computers and are willing to void the warranty. Suunto recommends taking their dive computers to a service center once every two years, or 200 dives, whichever comes first, for a battery change and to calibrate the device.

You also want to make sure you are using the device properly by reading the manual at least once, or check Suunto’s website to see their video guides on how to use the D4i. Topics of interest include ‘how to change dive settings’, ‘how to set alarms’, and ‘how to change transmission code.’

Battery Life and Replacement

The battery is estimated to last approximately two years under “normal” usage. That is, if you perform roughly 100 dives a year, then it will reach the end of its life around the two year mark. The life expectancy decreases faster the more settings you have on, such as a longer backlight duration or faster sampling rate.

Suunto recommends sending in their dive computers to a service center, but you can purchase Suunto D4i and D4i Novo battery replacement kits online. It is up to you whether you want to replace the battery yourself, which would void any warranty it has. A battery replacement kit will also come with an O-ring and silicone grease which you must apply to prevent water from seeping into the battery compartment.

An in-between option is to purchase a battery replacement kit and take it to your local dive shop to have them replace it for you. This option will keep your warranty intact and you can save some time and money.

Suunto D4i and D4i Novo Review: The Verdict

To conclude, we felt the D4i and D4i Novo are very solid dive computers. It can be used by both recreational scuba divers and freedivers, with the option to add wireless air integration support for more technical dives. It will do basically everything you want it to do at a great price.

The D4i has a reputation for being an all-rounder and it certainly lives up to that. You can even wear it as a wristwatch outside of diving. It looks great and works well both in and out of the water.

Some minor issues we had was that the Suunto was not designed with the intention for users to replace the battery themselves. Furthermore, while it does support wireless air integration, which is a big plus, it does not have a digital compass. As a result, technical divers would probably want a higher-end model which supports this function.

Overall, the level of customizability for different diving situations make the D4i extremely versatile. Even if the D4i is your first ever dive computer, its intuitive menus are easy to learn. It is also well-documented and similar to other Suunto dive computers so owners of other Suunto products should pick it up easily. We recommend it for beginners or recreational divers who want to grow with their dive computer.


  • Can be used by basically every diver, regardless of skill level.
  • Intuitive display that is user-friendly and easy-to-read.
  • Supports wireless air integration.
  • The RGBM Algorithm supports multiple dives in a day.
  • Sits comfortably on the wrist; can be worn as your everyday watch.
  • Buttons are easy to press.


  • Battery is technically not user-changeable.
  • Data will be lost once the battery is removed, so you have to back up your dive log to your computer before sending it off.
  • No digital compass.

If you are shopping for a new air integrated dive computer, we recommend you check out this review. You may also be interested in other Suunto dive computers, such as the Vyper Novo which you can read about here.