Best Dive Computers of 2021 – Dive Watch Review

These six best dive computers are just a handful of the data crunchers that hit the market this year. They cover the range from entry level to advanced, from wrist to console and from air integrated to hoseless. RDC test divers made multiple dives over a period of weeks getting to know these new computers. We found that not only are new computers getting more advanced there are also some new computers getting more basic and easier to use for the entry level diver. This trend offers more choices so you can get the right computer to fit your scuba diving style, whether it’s an occasional dive vacation or multi-gas tech adventure.

Recommended Best Dive Computers by RDC

Subgear XP

Mares Matrix

Best Dive Computers of [date format='Y'] - Dive Watch Review
Best Dive Computers of [date format='Y'] - Dive Watch Review

What Pushes Your Buttons?

The new computers in this review have anywhere from one to four buttons. They each let you scroll through menus, change settings, and view alternate screens during a dive. Surprisingly RDC test divers were split on the configuration they liked best. Some liked the simplicity of the single button design, after all it leaves no doubt which button to press. With single button computers you just press and release to scroll and press and hold to select. The drawback is you can’t go backwards in the menu. The other favorite button configuration was the three button option. In most cases this design lets you move forward or backward with two buttons while the third button is used to select the setting or function.

Algorithm Alchemy

It’s easy to get confused when reading the specs regarding the theoretical models used to calculate your deco status. Each computer is designed to reduce the risk of decompression illness. Some use a more conservative model, some are more liberal, and still others fall in the middle. Some of the newest computers can switch between two different algorithms like having two different operating systems on your laptop computer. Generally they can all be used more conservatively if you wish. Most have a Conservative Factor setting which reduces your No Deco Limit, and you can always add your own safety factor by making a safety stop and surfacing before reaching the limit.

Computer Reviews

Aeris A300 and A300 XT

Product Information
Aeris A300 and A300 XT Dive Computers

  • Three operating modes: Air/Nitrox, Gauge, and Free Dive
  • “TEC” mode
  • Depth, Dive Time Remaining
  • Price: $409.95 A300 Wrist; $639.95 A300XT Console
Not available. Check Aeris XR-1 Nx Computer Console at

The Aeris A300 and A300 XT computers are entry level friendly yet still have the features advanced divers want in a computer. The A300 offers three operating modes: Air/Nitrox, Gauge, and Free Dive, while the console version (A300 XT) drops the Free Dive mode but adds an SPG with a low air alarm and backlight, plus a compass. Both can switch between three Nitrox mixes up to 100-percent O2, and offer Dual Algorithm options with Deep Stop and Safety Stop functions.

What makes the A300 and A300XT easy to use is they can be set in a basic operating mode that has defaults for most settings making it “out of the box” simple for the new diver or used in “TEC” mode giving the advanced diver total control. The three-button interface is intuitive allowing you to easily navigate forward or backward through menus and settings, and return to the main screen from any page with the press of one button.

What makes the A300 and A300XT so easy to read are large numbers and bar graphs. Instead of overloading the screen with tons of data the A300 displays just the most important information: Depth, Dive Time Remaining, and bar graphs for tissue loading and ascent rate. This allows the numbers to be very large and the green, yellow, red bar graphs to stand out, allowing you to check your status easily at a glance while alternate screens fill in the details.

Test divers gave both the A300 and A300 XT high marks for ease of use and readability underwater with digit size rating excellent. Small icons required a little squinting but most felt this was a minor nit-pick. The Safety Stop display was considered excellent for it’s clarity and readability. The A300XT has a very bright backlight that lights up the SPG and computer module and was noticeable in less than dark conditions. The A300 computers come with a comprehensive user manual on CD and a handy Quick Start Guide. Both scored high for ease of use and understanding. The CD allows you to print out just the sections you want or the whole book, while the quick start guide gives you enough information to hit the water running.

Bottom Line

The A300 and A300XT offer the ease of the best basic computers with the features of the most advanced computers. They are the perfect choice for a new diver who is planning to advance their skills or the advanced diver who wants Tec functions with an uncluttered display.

Aeris A100

Product Information
Aeris A100 Dive Computer

  • Dual Algorithm – Pelagic DSAT & Z+
  • Depth alarm – ON/OFF, 10 – 100 meters
  • Elapsed Dive Time (EDT) alarm – ON/OFF, 10 – 180 minutes
  • Dive Time Remaining (DTR) alarm – ON/OFF, 5 – 20 minutes
  • Personal Conservative Factor – ON/OFF
  • Price: $309.95 Wrist; $389.95
Not available. Check Oceanic VTX OLED Computer at

The A100 is the epitome of an entry-level computer and it is fall down simple to use. It uses a single control button to access menus and settings. The A100 is a single mode Air/Nitrox computer that can be set up to 50-percent O2. It features an easy to read display with large numbers and high-resolution color bar graphs to show tissue loading and variable ascent rate. It offers a Dual Algorithm calculation option with automatic Safety Stop countdown timer.

The A100 features large digits and green, yellow, red bar graphs for a quick and easy glimpse of your dive status. Only the most vital information is displayed. Depth is displayed above Dive Time Remaining with large color coded bar graphs depicting tissue loading and ascent rate on the sides. Press the button to access an alternate screen showing Max Depth and Bottom Time, press again to see PO2, FO2, and O2 accumulation when using Nitrox.

Underwater the A100 was found to be one of the easiest to read with large numbers and simple layout. With just two numbers (Depth and NDL) and two bar graphs it’s impossible to get confused. The Safety Stop function was also one of the easiest to read and understand.

Bottom Line

They don’t make them any easier to use than the A100. You could learn to use it between the time you jump off the boat and hit the water. This is perfect for the new diver or the infrequent diver who forgets how to set their computer between vacations.

Cressi Leonardo

Product Information
Cressi Leonardo Dive Computer

  • Complete RGBM dive computer
  • Air and nitrox modes
  • Single easy button
  • Audible Alarm
  • Larger digits for easy reading
  • Price: $279.95 Wrist; $259.00 with USB PB Download Kit
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The Leonardo is a single gas, dual mode computer that is Nitrox programmable up to 50-percent O2, or can operate in Gauge mode. It runs on Cressi’s new 9-tissue RGBM algorithm developed by Bruce Wienke, and offers an optional Deep Stop function. There are settings for three personal safety factor levels and four altitude levels that can be used to add more conservatism. The Leonardo has visual and audible alarms plus a bright backlight display.

The Leonardo was one of our favorite data crunchers in this review. Although it’s a pretty basic computer it offers all the features and functions that beginning sport divers need. It is very user friendly with a screen layout that is easy to read and comprehend. Making changes to settings was not as intuitive as some other single button computers but after a few attempts we were able to program the Leonardo without using the manual.

In the water RDC test divers found the Leonardo was one of the easiest computers to read at a glance with more info than some but not so much that it clutters the screen. The top row shows Max Depth and Dive Time while the middle line has the largest numbers, showing the current Depth and No Deco Time remaining, and Temperature is at the bottom. Press the button to see an alternate screen with FO2 and PO2 info. The logbook stores 60 dives plus there is a dive history page.

Bottom Line

The Leonardo is one of the best entry level computers we have used. The numbers are large and the screen is easy to read making it a good choice for new divers.

Hollis DG03

Product Information
Hollis DG03

  • 3 operating modes (Air/Nitrox, Gauge with a timer function, Free Dive)
  • Pelagic Z+ algorithm
  • Price: $600 (add $360 for the optional transmitter)
Not available. Check Hollis TX1 at

This new wrist-mount data cruncher from Hollis offers three operating modes (Air/Nitrox, Gauge with a timer function, and Free Dive), it is Nitrox capable up to 100 percent O2, and it will let you program up to three gas mixes. It will also track your gas pressure and Air Time Remaining with the optional transmitter. The DG03 uses the Pelagic Z+ algorithm with optional Deep Stop function.

Our test DG03 came packaged in a very cool plastic storage case with a foam cutout to cushion the unit and a place to store the transmitter if you decide to go that route. We were able to define the functions of the three control buttons and program all surface and dive parameters with minimal hassle without the help of the manual and with plenty of time to spare before the anchor dropped for the first dive of the day.

In the water the DG03 proved to be an easy computer to use and read. The digits are large and well-organized, alternate screen data is easy to access, and the alpha-numeric display radically increases screen comprehension. A large bar graph for nitrogen loading cuts across the center of the screen for a quick check on your deco status. Ascent rate is monitored with a graph on the right and O2 exposure with a graph on the left side. When used with the optional transmitter you also have a digital readout of your air pressure and calculated air time remaining.

Bottom Line

The DG03 is a pretty nifty data cruncher for the advanced diver. Having the option to go air-integrated is cool, the storage box is a nice extra, the waterproof prompt card is full of good info and the price is pretty darn good.

Mares Matrix

Product Information
Mares Matrix Dive Computer

  • Full-Dot Matrix High Resolution Display
  • Full-Dot Matrix High Resolution Display
  • Tilt-Compensated Digital Compass with bearing Function
  • Air, Nitrox, Watch and Gauge Modes
  • Multi-Gas RGBM Algorithm
  • Price: $399.95
Shop now at

The new Matrix gets its moniker from its high-resolution, full dot matrix display. As a watch the Matrix has all you need including some rugged good looks. It uses four control buttons to navigate through menus and settings. The operating system is an easy study with the Quick Start Guide provided. On the surface the Matrix offers two different watch displays. A digital compass can be accessed in the watch mode allowing you to set a bearing even before you suit up.

As a dive computer the Matrix offers two modes Air/Nitrox and Gauge. In Dive Mode the main information displayed is Depth, Dive Time, NDL plus a tissue loading bar graph. There is an alternate screen that offers a “Profile” graph with the current Depth and Dive Time displayed. The Matrix can track up to 3-gas mixes from 21% to 99%. It offers an automatic Safety Stop and Deep Stop function. The Matrix uses the RGBM Mares-Wienke decompression model of 10 compartments, plus you can set an additional Personal safety factor in the Dive Settings menu.

Underwater the display was bold and easy to read. Depth is seen at the top while NDL is displayed in the center with dive time and other selected data at the bottom. A large tissue loading bar graph on the side is easy to read at a quick glance. We liked that the compass stayed on when activated and remained on until we turned it off. This is one of the best displays we have seen in a “Watch” style computer. The compass graphic was intuitive and the reference bearing and symbols were easy to read.

Bottom Line

The Matrix had all the functionality we needed and then some. We liked the size and clarity of the display and how the information was laid out. The compass was easy to read and functioned with the responsiveness of a traditional compass.

Subgear XP-H

Product Information
Subgear XP-H

  • Ultracompact unit
  • Nitrox compatible to 50 percent
  • Two-button navigation and settings adjustment
  • Full staged decompression capabilities
  • User-replicable battery in sealed compartment
  • Price: $399.95
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The XP-H is a compact air-integrated computer that strikes the perfect balance between what you want and what you need in a dive computer. Most divers will find all the features they need with this single gas, dual mode computer that’s not much larger than a traditional SPG. Nitrox can be set from 21% to 100% O2. In Gauge mode the XP-H tracks depth, dive time, PSI, and temp plus max and average depth without deco calculations, there is also a stopwatch function.

The XP-H uses the ZH-L8 ADT decompression model plus an optional 6-level Micro Bubble program for greater safety. You also have the option to turn on PDIS – Profile Dependent Intermediate Stops, similar to deep stops but based on your dive profile. Ascent rate is presented numerically and it offers visual and audible alarms plus a timer for safety stops.

The XP-H had a fast learning curve helped by the accompanying quick start guide and comprehensive user manual CD. The two-button design lets you scroll forward or backward through the main menu. Press and hold the right button to enter a sub-menu or select a setting. The left button takes you back one page and pressing both buttons takes you home.

Underwater we found the display to be clear. The numbers were large enough to read comfortably, especially after we bumped up the contrast setting of the LCD display. The sub-text icons were a bit small and required a little squinting for some of us older testers.

There are three lines of data on the screen. The top shows Depth and Dive Time. The middle shows NDL, and the bottom shows PSI and O2 exposure. This space also displays ascent rate. A very large nitrogen loading bar graph on the right side can’t be missed, and also functions as a battery level indicator. Alternate data such as max depth, temp, and time of day are accessed using the right button. The left button starts your safety stop timer and places a bookmark in your log profile.

Bottom Line

One of our testers called the XP-H an “entry level” air-integrated computer but that’s due to the price and not performance. The XP-H gives you everything you need in one small package.

Super Dive Computers

Of all the categories of gear in scuba diving, none can compare to the dizzying array of choices you get with scuba diving computers. From basic data crunchers like the ones covered in this issue’s Top Story, to the feature-packed top-end models, whatever your skill level, whatever your underwater interests, there’s a dive computer built just for you.

Recommended Computers and Reviews

But what about the ultimate dive computers, the crème de la crème, the ones that offer every feature in the data crunching book—plus a few more you never would have thought of. We like to call these the Super Computers.

Dive computing powerhouses, their displays are extra-large for easy reading, they use intuitive menu systems not unlike what you’d find on your personal computer, they provide lots of screens to view data from a variety of perspectives, they make use of eye-popping four-color graphics, and they offer a bevy of over-the-top extras you won’t find anywhere else. Take at look at these three Super Computers, presented in alphabetical order, and see if you agree that they’ve earned bragging rights to such a moniker.

Atomic Aquatics Cobalt

– The ultimate console dive computer

Atomic Aquatics Cobalt Dive Computer

  • Price: $899.95
  • 256K full color LCD display
  • Rechargeable battery
  • Leak-proof magnetic buttons
  • Air and Nitrox compatible to 99% O2
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Atomic Aquatics CobaltIf you’re looking for the state-of-the-art in your dive computer, and you prefer air-integrated console units over wrist-mount units, then the Cobalt is definitely the data cruncher for you. The Cobalt uses a large active matrix OLED (organic light-emitting diode) screen with big bright four-color digits against a black background for excellent contrast at depth. The display is divided into three basic sections for easy reading. Digits and graphics are shown in a variety of sizes and colors to reflect the importance of the information being presented.

The Cobalt allows you to program up to three gas mixes to 99 percent 02 and to switch between them at depth. A full-function planner and a 600-hour logbook that offers graphic displays of profiles are also on board, along with a great dive simulator and a 3D digital compass that will work at any angle and, once activated, will stay that way until you turn it off.

The Cobalt’s RGBM (Reduced Gradient Bubble Model) algorithm has been written especially for Atomic and offers three use levels—standard (the most liberal), moderate, and conservative. Plus you can add in personal information like age and exertion level which will have an impact on the algorithm’s conservatism level.

Atomic Aquatics CobaltThe Cobalt is powered by a lithium ion battery, and comes with an AC charger and a USB cord for charging off a PC. A PC download kit that works with both Windows and Mac is included, and the DC is designed to allow periodic firmware updates to its operating system software to enhance performance and improve reliability. Depending on what you set the screen brightness to, you can get up to about 40 hours of dive time and about six months of standby between charges. A twist-on quick-disconnect fitting lets you detach the DC from your regulator system for between-dive data tracking or storage.

What’s Really Cool About It

All the cool features aside, in our view the real benefit to this data cruncher is how simple it is to use. Power up and the first screen that appears is the Main Menu, which gives you a choice of six options, including Settings. From here you can program the entire computer—personal preferences, risk level, and all dive parameters—by following simple screen prompts that each offer a brief description of what the mode does. It’s incredibly easy. The Cobalt comes with an excellent owners manual but you may never open it, because you don’t really need it.

The Downsides

Atomic Aquatics CobaltWhile the contrast of bright color digits against a black background makes info literally pop off the screen at depth or on the surface when you’re standing in shade, in direct sunlight the Cobalt’s screen can be a bit hard to read. Also, relative to the overall size of the Cobalt’s big screen, we find the compass to be a little small. Finally, past RDC tests have shown that water can get trapped inside the quick-disconnect fitting. The solution to this, of course, is to use the quick-disconnect fitting. Separating the Cobalt from your reg system after a day of diving not only makes sense for secure storage, it also keeps the connection dry and corrosion-free.

Bottom Line

If you’re into advanced-level console-style dive computers, you simply can’t do better than the Cobalt. It’s simple to use, loaded with features, and packed with computing power.

Mares Icon HD net ready

– Going down in living color

Mares Icon Dive Computer

  • Price: $859.95
  • Hose less tank pressure transmission
  • Exclusive bidirectional communication
  • Displays tank pressure, time remaining and current gas consumption
Shop now at

Nobody does four-color like the Icon HD net ready. Using LCD (Liquid Crystal Display) with TFT (Thin Film Transistor) technology, the reds and oranges and greens and blues are simply stunning. But the Icon HD is not just another pretty face. You can program up to three gas mixes, with the capability of running nitrox to 99 percent. Hoseless air integration is available which tracks gas time remaining along with gas consumption.

Mares Icon HDA full-tilt four-color digital compass lets you simultaneously monitor your no-deco and bottom time and ascent rate while navigating through a dive. The Logbook stores more than 100 hours of dive time, and you can also load sea maps of dive sites that can be accessed while diving, plus store four-color photos for viewing on the surface.

At depth, you get a choice of two primary data screens that you can toggle back and forth, and each of these screens has its own alternate screen. There’s also a compass screen, and a map screen.

The Icon HD net ready leans conservative, and lets you program four altitude and three personal safety levels to maximize your safety cushion at depth.

Icon HD net ready comes nicely packaged in an armored pouch with lots of internal padding. Included are both printed and CD versions of the owners manual, a laminated quick reference guide, PC download software and a rechargeable lithium ion battery.

What’s Really Cool About It

Mares Icon HDThe cutting-edge color presentation on this DC is something that must be seen to be appreciated. Graphics are outstanding, and at-depth warnings literally leap off the screen. With its Smart Phone-style main menu and four button controls, navigating through the Icon HD net ready system couldn’t be easier. It’s also easy to set all computer and dive parameters simply by following the screen prompts. The compass is large and easy to see and use.
The Downsides

Mares Icon HDLike all LCD screens, the Icon HD net ready’s display can be very difficult to see in direct sunlight. At depth or in the shade it pops, but be prepared to squint if you’re trying to view the screen with the sun behind you. Also, all this color and screen brightness impacts battery power. To conserve energy the DC uses dual-level illumination that defaults to low power. To switch to high power you just press a button. But this can be somewhat annoying as you’re diving. To avoid this, you can set the screen to permanent high power, but that sucks up battery juice even more.

Bottom Line

With its vibrant colors, large compass, data-crunching capability and innovative menu system, the Icon HD net ready rivals its Super Computer brethren in ease of use, plus offers a wider variety of logging, mapping and photo storage features. Bonus: it now has a download interface that’s compatible with Mac computers and, according to Mares, soon Mac fans will also have the option to synchronize their logbooks with their iPhones and iPads.

Scubapro Galileo Sol

– Serious computing horsepower, and so much more

Scubapro Galileo Sol

  • Price: $599.00
  • Predictive Multi-Gas ZHL8 ADT MB algorithm
  • Hoseless gas integration provides tank pressure, true remaining bottom time (RBT)
  • Maximum operating depth: 1082ft/330m
Shop now at

The Galileo Sol doesn’t use color accents but it’s got all the other features that qualifies it as a Super Computer, plus it throws in a few unique goodies of its own. While not quite as intuitive as the newer operating systems of the Cobalt and Icon HD net ready, the Galileo Sol nonetheless uses an extra-large, well-appointed dot-matrix display that’s accessed via a three-button operating system. When navigating through the system, as screens change, button functions change as well as their labels, so it’s virtually impossible to get lost. The screen uses gray/black tones to highlight data and warnings, and dominant 02 and N2 bars to track gas loading.

Scubapro Galileo SolThe Galileo Sol gives you a choice of three distinct Dive Mode display screens on which to view your dive data. The “Light” display is clean and simple, showing dive time, depth, tank pressure and no-stop information with large bold digits. The “Full” display lays down virtually every bit of dive data you can possible think of on one highly organized screen. Then you’ve got your “Classic” display which offers a happy medium. You can rotate the Galileo Sol’s screen 180 degrees, giving you a choice of having the control buttons on the top or bottom of the unit. Also, by switching to alternate screens you can view a graphical representation of your dive profiles as well as track your tissue loading via a detailed saturation bar graph. Most recent upgrades include an “Apnea” free diving mode and software for tri-mix diving.

The DC’s hoseless air-integration system can read as many as four high-pressure transmitters at the same time. It calculates true remaining bottom time which takes into account tank pressure, breathing rate, depth and upcoming decompression obligations. Its memory lets you store your most recent 100 hours of dive information in surprising detail. Up to 100 gray-scale bitmap pictures can also be stored on the unit and accessed while diving. The digital compass is huge and user friendly, and the heart-rate monitoring system turns out to be a useful bonus.

Scubapro Galileo SolThe Galileo uses a special algorithm that takes into account heart rate for its workload computations. It also uses micro-bubble suppression technology to minimize micro-bubble formation and maximize your safety cushion. Overall, it falls about mid-range on the liberal/conservative chart; however, you can increase its conservatism by programming up to six micro-bubble suppression levels.

What’s Really Cool About It

Its lack of color gives the Galileo Sol an advantage when using it in sunlight. While screen visibility is quite good at depth and in the shade on the surface, it’s also quite good when the sun is shining brightly. The full-tilt compass is one of the easiest navigation tools we’ve ever used, and the heart rate monitor is turns out to be a really useful source of additional dive data.

The Downsides

Scubapro Galileo SolIf you consider the lack of color to be a downside, then there you go. But the lack of color also eliminates any issues with excessive power consumption, so in our book that’s a wash. In fact, this can actually be looked upon as an upside, since the battery doesn’t need to be recharged and will provide hundreds of hours of diving. And when its useful life is over it can be easily replaced by the user.

Bottom Line

If color’s not high on your wish list the Galileo Sol offers a tremendous amount of computer power, some really nice choices in screens and features, serious data crunching chops, and the heart rate monitoring feature is both cool and a beneficial extra. It comes in a nice storage case too.

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