Comparison Summary
The Garmin Descent G2 is the most versatile starting point for someone who wants a watch-style scuba and freediving computer that also works as an everyday sports watch. The Descent Mk3i 43 mm adds compatible wireless tank-pressure monitoring and diver-networking features for buyers who will use them. Suunto’s Nautic S is a compact, dive-focused alternative with sidemount support, while the Shearwater Peregrine puts a large two-button screen ahead of smartwatch features. For simpler recreational use, the Mares Puck 4 and Cressi Donatello offer different ways to keep controls straightforward.
Buying Guide
Sizing and Capacity
For a dive computer, capacity means both wrist fit and the dive profile it can manage. Garmin’s 43 mm Descent Mk3i is the clearer small-wrist choice than its 46 mm G2, but strap length and fit over a wetsuit still need checking. The Peregrine’s 2.2-inch screen and Descent X30’s 2.4-inch screen give buyers more display area at the cost of a less conventional watch feel. Check whether a listed dimension describes the computer itself or its packaging.
Gas capacity matters more than a broad “multigas” label. The Leonardo 2.0 and Donatello suit a diver using one nitrox mix; the Puck 4 supports up to three gases. The Nautic S supports multigas scuba, while the Mk3i, G2 and Sirius address more involved profiles. Choose those modes for a planned, trained use—not as a substitute for the instruction that use requires.
Feature Tradeoffs
Tank-pressure monitoring is optional, not an essential feature of every wrist computer. The Mk3i pairs with Garmin Descent T2 transceivers, the Nautic S and Ocean use Suunto Tank PODs, and the Sirius uses a compatible Mares tank module. Support does not establish that a transmitter is in the box: confirm the exact kit and the equipment needed for each cylinder before buying. The Peregrine, by contrast, deliberately focuses on its dive display and modes without air integration. (garmin.com)
Decide separately whether you want a daily watch. The G2 and Ocean make strong cases through sports features; the Mk3i adds advanced connected-dive functions. If those extras will go unused, a dive-focused Peregrine or Nautic S may be a better match. Surface GPS on several models helps with dive-site or entry-point information, but it should not be mistaken for an ordinary live underwater GPS position.
Best For, Avoid If
| Profile |
Recommended Product |
Why It Fits |
Avoid If |
| Diver replacing an everyday sports watch |
Garmin Descent G2 46 mm |
The Descent G2 combines multiple scuba and apnea modes with training features in a 46 mm watch. |
You require wireless tank-pressure readings from this computer. |
| Smaller-wrist diver planning to add tank monitoring |
Garmin Descent Mk3i 43 mm |
The 43 mm Descent Mk3i supports advanced dive modes and compatible Descent T2 pressure monitoring. |
You expect a transmitter to be included without confirming the exact kit. |
| Sidemount diver seeking a compact wrist computer |
Suunto Nautic S |
The Nautic S supports multigas diving and pressure readings from paired Tank PODs, including a two-transmitter sidemount setup. |
You do not want the compatible PODs needed for wireless pressure readings. |
| Sport diver prioritizing a large, uncomplicated screen |
Shearwater Peregrine |
The Peregrine has a 2.2-inch color display, two-button controls and a three-gas Nitrox mode. |
You want air integration or a compact daily smartwatch. |
| Recreational scuba diver who also freedives |
Cressi Donatello |
The Donatello has dedicated Free/Apnea and single-gas scuba modes plus a user-changeable battery. |
You need multigas scuba or assume phone logging works without an optional interface. |
| Diver who values display area over watch-like size |
Garmin Descent X30 |
The Descent X30 offers a 2.4-inch color display and customizable data pages. |
You want a compact daily watch or tank-pressure integration. |
Key Specs to Compare
Compare dive-mode battery figures with their conditions attached. The Peregrine is listed at up to about 30 hours at medium brightness, and Suunto lists up to 60 hours of dive time for the rechargeable Nautic S. The Ocean listing says up to 40 hours in dive mode, while Suunto’s published product information describes a 40–60-hour dive range depending on configuration. Plan around your settings and charging opportunities rather than treating any maximum as a guaranteed trip duration. (shearwater.com)
For decompression settings, look at the exact mode as well as the named algorithm. The Puck 4 lists adjustable gradient factors and three-gas support; the Peregrine separates single-gas Air and Nitrox modes from its three-gas Nitrox mode. Gauge or bottom-timer mode is not the same as receiving scuba decompression information. Display type is another practical spec: compare the Puck 4’s segmented screen with the color displays on the Peregrine and larger Garmin X30.
Setup and Handling Considerations
Before a dive, confirm the selected scuba or freediving mode, breathing-gas settings, alarms and remaining battery on the computer itself. This is especially worth practicing on a one-button Leonardo 2.0, Donatello or Puck 4: fewer controls do not remove the need to know the menu. Divers using a Nautic S should enter its pre-dive screen to confirm gas settings rather than relying on automatic dive start. (us.suunto.com)
If tank pressure is part of your decision, verify the compatible transmitter, pair it as directed and check the displayed cylinder information before entering the water. For post-dive logs, the G2 uses the Garmin Dive smartphone app and the Suunto models use the Suunto app. The Cressi computers take a different approach: their compatible Bluetooth docking interface is a separate accessory unless an exact kit includes it. (store.cressi.com)
Maintenance and Longevity
Choose a battery approach that suits your trips. The rechargeable G2, Peregrine, Nautic S, Ocean and Sirius need charging access; the Donatello and Leonardo 2.0 have user-changeable batteries. Shearwater describes the Peregrine’s internal battery as replaceable through authorized service rather than by the user. Check the relevant manual before opening a battery compartment or arranging service. (shearwater.com)
Before each trip, inspect the strap, screen and controls, and allow time to address damage or a charging problem. An extendable or changeable strap matters if the computer must fit over exposure protection. Keep app and computer software requirements in mind for connected features, particularly if a feature depends on a stated software version.
Reliability Signals
The most useful buying signal is precise product documentation: an identifiable model or part number, stated scuba modes, a dive rating and clear instructions for setup. For example, Garmin’s G2 manual specifies dive-design compliance alongside its 10 ATM rating; the rating alone would not describe its scuba-computer functions. The Peregrine’s published modes likewise establish what its three-gas capability does—and do not turn it into a trimix computer. (www8.garmin.com)
Check the listing against the maker’s documentation when wording is broad. “Wireless gas analysis,” “connected logs” and “GPS” can each depend on an accessory, phone or surface conditions. A useful product description makes those conditions visible rather than presenting every supported function as ready to use out of the box.
How to Compare Reviews
Look for accounts of the exact model, battery arrangement and dives resembling yours. Feedback about the Peregrine’s two-button navigation is more relevant if you want a large dive-focused screen; feedback about the G2’s daily wear matters more if it will replace a sports watch. Separate reports on a Mk3i used with a Descent T2 from reports on the watch alone, and distinguish a Nautic S used with Tank PODs from one used without pressure monitoring.
When reading complaints about log transfer, identify the accessory and phone setup involved. A Leonardo 2.0 or Donatello paired through Cressi’s optional interface is not the same setup as a watch with built-in app syncing. Give the most weight to descriptions that state the dive mode, conditions and equipment involved, rather than a broad impression that cannot be tied to your intended use.
Common Mistakes
Do not buy from the word “dive” or a water rating alone: confirm that the exact model supports the scuba mode and gas mix you need. Do not assume a freediving or Gauge mode supplies scuba decompression calculations. Likewise, do not infer that the G2 has the Mk3i’s air integration, or that the X30 inherits the different X50i’s connected-dive features. (www8.garmin.com)
Avoid comparing smartwatch standby claims with dive-mode runtime, or treating surface GPS as continuous underwater navigation. Finally, check the precise package contents. A transmitter, Cressi logging interface or alternate strap can materially change how suitable a listing is even when the computer model is right.
Frequently Asked Questions
Can a freediving mode replace a scuba mode?
No. Choose a computer with a scuba mode for the breathing gas and dive profile you plan to use. A dedicated apnea mode records breath-hold activity; Gauge or bottom-timer mode does not provide the same decompression information as a configured scuba mode.
Does an air-integrated dive watch include a transmitter?
Not necessarily. The Mk3i, Nautic S, Ocean and Sirius support compatible wireless tank-pressure accessories, but inclusion depends on the exact package. Check both the transmitter model and kit contents.
Is GPS useful underwater?
Surface GPS can help mark entry and exit locations or find a dive site. It is not ordinary continuous underwater GPS navigation. Suunto Ocean’s underwater route information is assembled for review in the app after a dive.
Which of these computers avoids recharging?
The Cressi Donatello and Leonardo 2.0 have user-changeable batteries. That suits divers who prefer replacing a cell, while rechargeable models offer a different routine: charge them before the trip and check remaining power before each dive.
Final Recommendation
Choose the Garmin Descent G2 46 mm if you want one wearable for recreational or more advanced scuba, freediving and everyday training. If wireless tank pressure is central to your plan and a 43 mm case suits your wrist, choose the Garmin Descent Mk3i instead—after confirming the compatible Descent T2 equipment and exact kit contents.
