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Jon Whittle

The Best Dive Computers of 2021

ScubaLab tests 11 new scuba diving computers
By Robby Myers | Updated On December 1, 2021
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The Best Dive Computers of 2021

Scuba Diving's independent ScubaLab team tested 11 of the newest wrist and console dive computers on the market. Read on to see how we compared computers head-to-head, or navigate to the reviews of specific computers here:

How We Test

Our test evaluated two aspects of a computer’s performance: how easy it is to operate and understand before, during and after a dive, and an objective measure of its decompression algorithm relative to other computers in the test.

Test-Dive Protocol

Test divers evaluated computers in nine categories. Test dives were conducted at Blue Grotto Dive Resort in Williston, Florida, where divers recorded their scores in written comments about their experiences using each computer. Test categories were:

  • Intuitiveness and ease of operation, including configuring settings
  • General ergonomics, such as size and shape, comfort, and effectiveness of buttons, straps
  • Ease of reading screen at the surface, including in sun
  • Ease of reading screen underwater, including performance of backlight
  • Overall quality of dive data display, including selection, layout and presentation of data, with a focus on how clearly it presents critical dive information
  • Usefulness and ease of accessing alternate dive screen data
  • Safety-stop performance, including alerts and timer
  • Ease of accessing and usefulness of surface interval data, including no-fly time
  • Onboard log data, including ease of access

ScubaLab staff also tested computers in a bench-top compression chamber to observe screen displays, warnings and alarms in conditions not suitable for testing by divers, such as rapid ascents and missed deco stops. The goal of these tests is to gauge how well each computer performed in providing clear, understandable guidance in those conditions.

Objective Test Protocol

To gauge the relative conservatism or liberalism of the computers’ algorithms, they were subjected together to a series of four dive simulations in the University of Southern California Catalina Hyperbaric Chamber. Meant to simulate a day of diving, the multistage profiles were: 100 feet/55 minutes; a one-hour surface interval; 70 feet/45 minutes; a two-hour surface interval; 80 feet/45 minutes; a one-hour surface interval; and 60 feet/40 minutes.

Download full chamber-test NDL readings for each computer here. Special thanks to Catalina Hyperbaric Chamber director Karl E. Huggins and operators Armen Bagdasarian, John-Aaron Bozanic, Tom Carr, Larry Harris, Mike Peterson and Ted Sharshan.

Computers Below $450

Aqualung — I330R

Aqualung I330R Testers Choice

Price $359
Contact aqualung.com

Jon Whittle

Measuring just over an inch wide, the i330R uses an uncluttered layout and bold, colorful characters to maximize visibility while retaining a wrist-friendly size. “Terrific display, with excellent use of color to make data stand out,” one test diver commented. The computer’s display took the top score for visibility at depth, but suffers from glare at the surface, making it difficult to read in full sun. Its two-button operation is straightforward and intuitive, making menus and settings, in the words of one test diver, “easy to access with little experience.” Log data is visually appealing but very basic. The dive display is similarly simple, but does feature a handful of alternate screens, including gas-mix information and a timer. Attention-grabbing audible alerts are accompanied by flashing on-screen prompts, which make good use of the color display. For example, NDL will change from green to yellow and finally to red as no-deco time decreases. Although not all testers were fans of the computer’s NATO strap, the i330R’s lightweight, compact profile helped it score very good for overall ergonomics. “Perfect size and shape,” one tester noted. The computer was a favorite among test divers. Offering excellent ease-of-use and a crystal-clear color display, the i330R is our Testers Choice for dive computers under $450.

DOWNLOAD Bluetooth or USB cable
BATTERY Sealed rechargeable lithium
MODES 4; Air, Nitrox, Gauge and Freedive
GASES 3; 21-100% O2
ALGORITHM In our chamber dives, NDLs were on the conservative side

Cressi — Donatello

Cressi Donatello Dive Watch

Price $279
Contact cressi.com

Jon Whittle

This computer’s one-button operation is intuitive and easy to learn, allowing even newer divers to grasp the basics with little instruction. “Simple and easy to access,” is how one tester described it. While its dimensions are reminiscent of a hockey puck, it still scored good for ergonomics. The nearly 2-inch high-contrast screen scored excellent for ease of reading at the surface, even in bright, sunny conditions. Activating the computer’s backlight requires the user to hold down the button for a little longer than expected, and hurt its score for visibility at depth. The data on the display is labeled and well-segmented, making it easy to reference dive info at a glance. The single alternate dive screen is pretty basic, but provides some useful data, including time of day. Despite its simple display, testers were pleased to find that the Donatello’s safety-stop countdown includes both minutes and seconds. Audible chirps and flashing characters accompany alerts. Simple and easy-to-understand, the Donatello is well-suited for novice divers, or any diver looking for a dependable, no-fuss dive instrument.

DOWNLOAD Bluetooth or USB interface
BATTERY User-replaceable
MODES 4; Air, Nitrox, Gauge, Freedive
GASES 1; 21-50% O2
ALGORITHM NDLs were slightly conservative in our chamber dives

Seac — Screen

Seac Screen wrist dive computer best buy

Price $299
Contact seacsub.com

Jon Whittle

Large but not bulky, the Screen’s low-profile design took the top score for ergonomics in its category. “Feels good on the wrist,” one tester commented. “Big, but pretty slim and sleek,” another said. The computer scored good for intuitive operation, but a few functions, such as pressing both buttons simultaneously to back out of certain menus, can be frustrating until a new user commits them to memory. The nearly 2-inch-wide display features large, bold characters and provides them with plenty of breathing room. It took top score for ease of reading at the surface and was scored very good at depth. During the dive, the central dot matrix display can look a little empty, featuring just the NDL. But, during deco and safety stops, the remaining space provides clear instructions for stop depth and time—although the countdown does not include seconds. Dive logs are simple, and display most info without needing to enter into a submenu for individual dives. Easy to read and use, and surprisingly comfortable, the Screen was a favorite among test divers. It is our Best Buy for dive computers under $450.

DOWNLOAD USB cable
BATTERY User-replaceable
MODES 3; Scuba, Gauge, Freedive
GASES 2; 21-99% O2
ALGORITHM In our chamber dives, NDLs were on the conservative side

Tusa — TC1

Tusa TC1 dive computer

Price $329.95
Contact tusa.com

Jon Whittle

Touting watchlike dimensions and ergonomics, this computer combines beginner-friendly functionality with a premium look and feel. It scored very good for ergonomics and earned tester praise such as, “great size, buttons just right.” Menus are logical, but feature a lot of options, which can be a bit overwhelming at first, earning just good scores from testers for intuitive operation. Bold characters and a good backlight make the computer very easy to read at the surface and at depth. The dive display is small and a bit crowded, packing in so much info that it doesn’t even bother with alternate screens. “Surprised I can read it as well as I can, but still hard to read at a glance. Often takes a bit of staring,” one tester observed. Fortunately, the TC1 gives divers the option to use either the full dive display or a simplified interface for a cleaner appearance. Vibrating haptic feedback is an excellent attention-grabber and accompanies audible and visual alerts. Dive logs are very rudimentary and can’t be downloaded, but include a simplified depth-profile graphic that earned very good scores.

DOWNLOAD None
BATTERY Sealed rechargeable lithium
MODES 3; Scuba, Gauge, Freedive
GASES 1; 22-56% O2
ALGORITHM NDLs were about average in our chamber dives

Computers Above $450

Atmos — Mission One

Atmos Mission 1 dive computer

Price $479.95
Contact atmos.app

Jon Whittle

This dive computer features smartwatch functionality, enabling divers to receive text, email and other notifications from their smartphone while at the surface. It also uses GPS to mark dive entry and exit points. Scoring very good for ergonomics, its compact, watchlike design sits easily on the wrist. The 1.2-inch high-resolution color screen proved very easy to read in all conditions, especially at depth. The dive display was scored very good, and uses large characters to prominently display critical dive info. Colorful visual alerts provide clear instruction and are accompanied by audible chirps and unmissable vibrations. “Large and easy to see,” and, “What a great screen, with excellent readability and a great layout,” were typical of tester comments. Testers also liked the simple compass overlay on the main dive screen. “Excellent. Very clear,” more than one tester observed about the computer’s safety stop. Logs show all data at a glance, and feature an interactive dive profile. With a highly visible, easy-to-understand color display, plus great ergonomics and haptic alerts, the Atmos One was a favorite among test divers.

DOWNLOAD Bluetooth or USB cable
BATTERY Sealed rechargeable lithium
MODES 4; Air, Nitrox, Gauge, Freedive
GASES 1; 21-40% O2
ALGORITHM We set it for liberal no-deco times, but you can select preset gradient factors or customize your own

Garmin — Descent MK2S

Garmin MK2S Testers Choice

Price $999.99
Contact buy.garmin.com

Jon Whittle

With a 43 mm case and a weight of about 2 ounces, the Mk2S is the smallest, lightest computer we’ve ever seen. Pleasing to the eye, and comfortable to wear and operate, it took top score for ergonomics. The 1.2-inch high-resolution color display is equally impressive, with excellent visibility and a sleek layout that presents data cleanly and clearly, with depth and NDL visible at all times. Testers were especially fond of the intuitive ascent/descent graphic. Alerts provide clear instruction and are accompanied by haptic feedback as well as audible tones. Simply double tapping the screen will cycle through the alternate dive displays, which can be customized and provide divers with a stopwatch and digital compass. With a host of data, including a dive profile graphic and GPS coordinates, the computer’s dive log scored excellent. The Mk2S also offers robust GPS, smartwatch and fitness capabilities, but remains incredibly easy to pick up and use, scoring excellent for intuitive operation. A favorite among testers, with outstanding performance, the Descent Mk2S is our Testers Choice.

DOWNLOAD Bluetooth or USB cable
BATTERY Sealed rechargeable lithium
MODES 4; Scuba, CCR, Gauge, Freediving
GASES 12; Air, Nitrox and Trimix up to 100% O2
ALGORITHM We set it for liberal no-deco times, but you can select preset gradient factors or customize your own

Scubapro — A2

Scubapro A2 dive computer

Price $709
Contact scubapro.com

Jon Whittle

Aimed at advanced divers, the air-integrated A2 supports trimix, sidemount and closed-circuit rebreather diving. With a low-profile design and tactical styling, it scored very good for ergonomics. Menus and settings can be a bit confusing, but a quick glance through the manual and some fooling around will quickly sort out most of the computer’s idiosyncrasies, which include a handy shortcut to quickly change gas mixes from the top menu. The display is well-labeled and uncrowded, with high-contrast digits and a powerful backlight. It took top score for surface reading. A dot matrix display used in the center further increases visibility of important data, especially during alerts, when critical data is boldly displayed on the matrix using a reverse-black background. The A2 provides a ton of secondary info during a dive, but displays it on the matrix one at a time, requiring a lot of button presses to cycle through all the options. The A2 has a digital compass, and when used with a tank transmitter and heart-rate monitor, the computer can use gas consumption and your workload to provide a precise calculation of remaining bottom time.

DOWNLOAD Bluetooth
BATTERY Dealer-replaceable
MODES 6; Scuba, CCR, Gauge, Freediving, Sport, Swim
GASES 8; 21-100% Nitrox, Trimex
ALGORITHM NDLs were slightly conservative in our chamber dives

Shearwater — Peregrine

Shearwater Peregrine Best Buy

Price $495
Contact shearwater.com

Jon Whittle

The Peregrine makes the most of its 2.2-inch color display with large characters that are easy to see at a glance. It scored very good for its display, and for ease of reading. “Nice design. Important stuff is obvious” and “Well-laid out, with important info front and center” were typical comments. Alternate screens provide a suite of secondary data, which can be customized with user-selected data fields, but no compass. Logical and easy-to-grasp, the computer’s two-button interface features handy on-screen prompts and tied the top score for intuitive operation. “Super simple operation,” is how one tester described it. Divers also liked the computer’s use of haptic feedback to call attention to alerts, which must be acknowledged before disappearing. Weighing about 6 ounces, the computer is heavy enough that it may bother smaller divers over a long dive, but its low profile helped it take a very good score for ergonomics. “A bit heavy, but not bad for the package and readability,” one diver noted. With very good scores across the board, the Peregrine was a favorite among testers. It is our Best Buy.

DOWNLOAD Bluetooth
BATTERY Sealed rechargeable lithium
MODES 4; Air, Nitrox, 3 Gas Nitrox, Gauge
GASES 3; 21-100% O2
ALGORITHM We set it for liberal no-deco times, but you can select preset gradient factors or customize your own

Suunto — Eon Steel Black

Suunto Eon Steel Black dive computer

Price $1,099.95
Contact suunto.com

Jon Whittle

The Eon Steel Black uses a simple three-button operation that is very intuitive and user-friendly. “Very straightforward,” one tester commented. Testers were quick to label the computer, measuring 2½ by 4 inches and built like a brick, as “big.” But despite its beefy dimensions and flat, smooth back, which made it prone to sliding around, it scored very good for ergonomics. The 2-inch color display suffers from glare at the surface, but is very clear at depth. Data is presented using large, bold characters with plenty of space in between. “Feels a little empty. Screen could be half the size for all of the data that is presented,” one tester observed. The digital compass is simple and easy to use, as is the timer. Dive alarms use loud, easy-to-recognize tones. In addition to choosing between two different algorithms, divers can also pick between two decompression profiles. Scored very good by testers, dive logs are easy to access and feature a wealth of data, including an interactive profile. With wireless air-integration with up to 20 transmitters and advanced modes for CCR and trimix, the Eon Steel Black provides a heavy-duty instrument for advanced divers.

DOWNLOAD Bluetooth and USB cable
BATTERY Sealed rechargeable lithium
MODES 4; Air/Nitrox, CCR, Trimix, Gauge
GASES 20; 5-99% O2, 0-95% Helium
ALGORITHM Set to Suunto’s Fused RGBM2 algorithm, NDLs were more liberal in our chamber dives

Console Computers

Cressi — Michaelangelo Console

Cressi Michaelangelo Console

Price $469.95
Contact cressi.com

Jon Whittle

The Michelangelo’s high-contrast display provides excellent visibility at the surface and features a backlight for easy reading at depth. The segmented screen is labeled and uses bold characters to make vital data distinguishable at a glance. The one-button operation is identical to the Donatello. Simple and intuitive, it seems even better suited to a console design, which places the button naturally under your thumb. Constructed out of Desmopan and polycarbonate materials, the console boot is lightweight, and its slim profile sits easily in the hand. The submersible pressure gauge uses a fluorescent dial for improved visibility at depth, and displays pressure in both imperial and metric—although the neon-orange color used for imperial can be difficult to read. Both instruments are set at an angle to create a more natural, ergonomic reading position. The computer features two-tank switching, and dive logs can be downloaded using an optional USB or Bluetooth interface. Simple and reliable, the Michelangelo is a user-friendly dive instrument well-suited to beginner divers.

DOWNLOAD Optional Bluetooth or USB interface
BATTERY User-replaceable
MODES 4; Air, Nitrox, Gauge, Apnea
GASES 2; 21-99% O2
ALGORITHM NDLs were slightly conservative in our chamber dives

Seac — Screen Console

Seac Screen Console dive computer

Price $399
Contact seacsub.com

Jon Whittle

The Screen’s almost 2-inch-wide display provides easy viewing, even when held at arm’s length. This is especially true of data in the dot matrix display that stretches across the center of the screen. However, during a typical dive, this field is left empty except for the remaining no-deco time. It is populated with safety-stop and decompression information, when appropriate. The large computer is also very flat, providing for an incredibly thin console. “Fits well in the hand. Ergos work well as a console,” one diver observed. The computer’s two centrally located buttons are easy to reach and very responsive. Operation is identical to the wrist-mount version, and aside from a few quirks to work out, provides a user-friendly, intuitive operation. The large submersible pressure gauge isn’t quite as big as the Screen, but it’s just as easy to read, with prominent imperial markings on a clean background.

DOWNLOAD USB cable
BATTERY User-replaceable
MODES 3; Scuba, Gauge, Freedive
GASES 2; 21-99% O2
ALGORITHM In our chamber dives, NDLs were on the conservative side

Ask the ScubaLab Director

Q: Do I really need to read the manual? A: Most computers come with a quick-start guide. While handy for acclimating quickly to a new computer, these guides are no substitute for a thorough read-through of the owner’s manual. Reading the manual will give you detailed instruction on the computer’s features, functions and displays, and will ensure you get the most out of your dive computer and know how to safely follow its instruction at depth.


Seeing is Believing

Display size is an important factor when it comes to the visibility of a dive computer’s screen. The larger it is, the more space is available for larger characters or for a clean, clear presentation of dive data. On the other hand, a bigger screen often means a bulkier, beefier computer. What’s the solution? While there’s no perfect answer to the puzzle, many manufacturers have taken different approaches to this delicate balancing act. The Seac Screen and Shearwater Peregrine both feature a wide rectangular screen that fits plenty of data combined with a thinner profile and slightly curved back for improved ergonomics. Garmin’s Descent Mk2S is one of the smallest dive computers we’ve ever seen, but its high-visibility color display and organized layout allowed it to take excellent scores for visibility of its display.

What's the Buzz?

Audible alarms are an important tool for a dive computer vying for attention, but they can be difficult to discern in a crowd. Every diver at one time or another has probably checked their dive computer at the sound of an alarm, only to realize the sound was coming from another diver’s computer. Vibrating alerts, also referred to as haptic feedback, are unmistakable and minimize the confusion, as they can only be felt by the person wearing the device. Though almost nonexistent in dive computers a few years ago, multiple computers in this year’s lineup— to the delight of test divers—have adopted haptic alerts in addition to their audible and visual alarms.