Shearwater Perdix vs Garmin Descent G2 2026 — Which Dive Computer?

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Buy the Shearwater Perdix 2 if diving is the point. It is a dedicated dive computer built for divers who are serious about the water, with a screen and a battery designed around that one job. Buy the Garmin Descent G2 if you want a real everyday smartwatch that happens to dive seriously too. For most divers asking which is the better dive computer, the answer is the Perdix 2. For the diver who wants one device on their wrist for diving, running, sleep tracking, and turn-by-turn navigation back to the car, the G2 is the smarter buy.

Both are excellent. They are not really competing for the same wrist. The question that decides it is whether you want the best tool for diving, or the best single device for a life that includes diving. Read on if you are torn, because the trade-off is sharper than the spec sheets make it look.

Quick Picks

I recommend the Shearwater Peregrine and Perdix family in my main dive computer guide. This comparison answers a different question: what happens when the choice is between a purpose-built dive computer and a do-everything smartwatch that also dives. That is the real Shearwater versus Garmin decision most divers are actually making.

The Shearwater Perdix 2: A Dive Computer That Does Nothing Else, and Does It Perfectly

The Perdix 2 is what you strap on when the dive is the priority and you want zero compromise on the data in front of your face. It does not count your steps or buzz when you get a text. It shows you a dive, beautifully, and it is built to keep doing that for a decade.

Start with the screen, because it is the thing owners never stop praising. The 2.2-inch color LCD runs at 320 by 240 with an LED backlight, and it stays legible at the angles your wrist actually sits at while you are finning. In a silty quarry, in the green water of a Great Lakes wreck dive, at the back of a Florida cavern where your light is the only light, the Perdix 2 reads instantly. There is no menu-diving to find your no-deco time. The number you need is the biggest number on the screen.

The battery is the other thing. The Perdix 2 runs on a single standard AA cell that you replace yourself. A lithium AA delivers up to around 60 hours of dive time, and when it dies you swap it in the parking lot in thirty seconds with a battery you can buy at any gas station on earth. No charging cable, no worrying whether you remembered to plug it in the night before a 6am boat, no slow death of a sealed rechargeable three years from now. For travel diving and remote diving this is not a small thing. It is often the whole argument.

Then the capability. The Perdix 2 runs Buhlmann ZHL-16C with configurable Gradient Factors out of the box, and you can unlock VPM-B and DCIEM if you want them. It handles air, nitrox, three-gas nitrox, open-circuit trimix decompression, and closed-circuit rebreather diving with fixed setpoints. It has a proper 3-axis tilt-compensated digital compass, and it connects to up to four wireless transmitters so you can see live tank pressure from your back gas and your stage bottles on one screen. Depth rating is 260 meters, roughly 850 feet, which is far past anywhere you will ever go and a sign of how the whole computer is built.

What owners actually report. Scroll ScubaBoard or r/scuba and the Perdix 2 pattern is remarkably consistent: people buy it and stop shopping. The most common complaint is purely cosmetic, that it is a chunky black rectangle and looks like a dive computer rather than a watch, because it is one. The praise is always the same three things: display readability, battery you control, and Shearwater software updates that keep improving a computer you already own. Almost nobody regrets it.

Get the Shearwater Perdix 2 on Amazon →

The Garmin Descent G2: A Genuine Smartwatch That Dives Hard

The G2 starts from the opposite end. Garmin built a real smartwatch first, then made it a serious dive computer second, and the surprise is how little it compromised on the diving.

The display is a 1.2-inch AMOLED under a sapphire lens, and it is gorgeous. On the surface it looks like any premium Garmin watch, which is the point: you wear it to work, to the gym, to bed, and on the boat. Underwater that AMOLED is bright and sharp, though it is a round watch face showing dive data rather than a big rectangular dive screen, so there is less raw real estate than the Perdix 2 gives you.

What genuinely impressed me is the dive capability. The G2 is not a toy. It tracks single-gas and multi-gas diving including nitrox and trimix, closed-circuit rebreather, gauge mode, and apnea and freedive modes. That is a deeper feature set than most divers expect from something that looks like a running watch. The case is dive-rated to 100 meters, around 330 feet, which covers all recreational diving and most of what a wrist-mounted computer is sensible for.

Then there is everything the Perdix 2 does not even attempt. GPS marks your entry and exit points so you can find the same reef or the same shore exit next time. The full Garmin health and fitness suite tracks your heart rate, sleep, training load, and runs, rides, and swims when you are dry. Battery runs up to around 10 days in smartwatch mode, and it charges on a cable like any watch. You wear this thing all day every day. The Perdix 2 lives in your dive bag between trips.

Where the G2 gives ground. Two things. First, no air integration: the G2 does not pair with a tank pressure transmitter at all, so you are still reading your SPG for gas. If seeing tank pressure on your wrist matters to you, that is a hard stop. Second, the rechargeable battery. It is convenient day to day, but it is sealed, it degrades over years, and it cannot be swapped at the dock or on a liveaboard with a spare cell in your pocket.

Get the Garmin Descent G2 on Amazon →

Head-to-Head

Who Should Buy Which

Buy the Shearwater Perdix 2 if diving is the priority and you want the best possible tool for it. You want a screen you can read instantly in bad water, a battery you control with a spare AA in your save-a-dive kit, and air integration so your tank pressure sits on your wrist next to your no-deco time. If you are heading toward technical diving, or you already dive trimix, stages, or a rebreather, the Perdix 2 is not just the better choice, it is the obvious one. This is the computer experienced divers buy and keep.

Buy the Garmin Descent G2 if you want one device that does everything and you do not want a dedicated dive computer cluttering up a drawer. You will wear it daily as a genuinely excellent smartwatch, track your fitness and sleep, use GPS to find dive sites and exits, and still have a capable nitrox-to-trimix computer on your wrist when you splash. If you dive a couple of trips a year and live an active life the rest of the time, the G2 earns its place on your arm 365 days a year in a way the Perdix 2 never will.

Buy neither if you are on your first 20 or 30 dives and still deciding whether the hobby is for you. A [Cressi Leonardo or Mares Puck Pro](/guides/cressi-leonardo-vs-mares-puck-pro) does everything a new diver needs for a fraction of the money. Buy the premium computer when you know you are committed.

The Honest Case Against Each

Against the Perdix 2: it is a single-purpose instrument. It looks like a dive computer because it is one, and it sits in your bag between trips doing nothing. If you were hoping for a watch you also wear to the office, this is not it. The G2 genuinely is. Paying Perdix 2 money for a device you use only on dive days is a real cost if you do not dive often.

Against the G2: the missing air integration is the one that stings, because everything else about it suggests a more capable computer than it is allowed to be. For a recreational diver that is fine, but a serious diver who wants gas pressure on their wrist will outgrow it. And the sealed rechargeable battery, brilliant for daily wear, is exactly the wrong choice for a remote liveaboard week where there is nowhere reliable to charge.

What to Avoid

The original Shearwater Perdix (first generation): the Perdix 2 superseded it with a better display, more memory, and ongoing firmware support. The buyable listings today are the current Perdix 2, which is what you want. Do not pay near-current prices for an old first-gen unit on the used market unless the discount is steep and the condition is excellent.

The Garmin Descent Mk3i, if all you need is the G2's job: the Mk3i is superb and adds air integration and a larger AMOLED, but it costs dramatically more. If you want a Garmin dive smartwatch and do not need tank-pressure integration, the G2 delivers the experience for far less. Spending up to the Mk3i for features you will not use is the classic over-buy in this category.

Grey-market Shearwater units: Shearwater pushes firmware that includes decompression model refinements and safety-relevant fixes, and warranty support runs through authorized dealers. A dive computer is life-support data. The savings on an unsupported overseas unit are not worth running stale firmware at depth with no warranty path.

FAQ

Is the Garmin Descent G2 a real dive computer or just a watch with a dive app?

It is a real dive computer. It runs single-gas, multi-gas nitrox, trimix, closed-circuit rebreather, gauge, and freedive modes on a Buhlmann ZHL-16C with Gradient Factors algorithm, and the case is dive-rated to 100 meters. The only meaningful dive feature it lacks versus the Perdix 2 is air integration.

Does the Shearwater Perdix 2 work as an everyday watch?

No, and it does not try to. It has no smartwatch features, no fitness tracking, and no GPS. It is a dedicated dive computer that you put on for diving and take off afterward. If you want something to wear all day, the G2 is the one in this matchup built for that.

Which has better battery life for a liveaboard or remote trip?

The Perdix 2, decisively. It runs on a single user-replaceable AA cell, so you carry spares and never depend on charging infrastructure. The G2 is rechargeable and lasts around 10 days in smartwatch mode, which is plenty at home but a liability somewhere with unreliable power.

Can the Garmin Descent G2 use a tank pressure transmitter?

No. The G2 does not support air integration of any kind. If you want live tank pressure on your wrist, you need the Perdix 2 (up to four transmitters) or step up to Garmin's air-integrated Mk-series.

Does the Perdix 2 come in a titanium version?

Yes. Shearwater sells a standard Perdix 2 and a Perdix 2 Ti with a titanium bezel and buttons. The diving capability is identical; the Ti is about durability and finish. Either is the current-generation Perdix 2 and the right Shearwater to buy today.

What I'd Buy Today

If the question in your head is simply which is the better dive computer, buy the Shearwater Perdix 2. The display, the swappable AA battery, and true air integration make it the tool serious divers reach for and keep for a decade.

Get the Shearwater Perdix 2 on Amazon →

If you want one device that dives seriously and then runs the other 360 days of your year, buy the Garmin Descent G2. It is a genuinely excellent smartwatch that also happens to be a capable nitrox-to-trimix computer.

Get the Garmin Descent G2 on Amazon →

The first time your no-deco time is the clearest thing in murky water, or the first time your watch guides you straight back to the shore exit after a long swim, you understand why these two computers both have devoted fans. They solve the dive from opposite directions. Pick the direction that fits your diving, and go get wet.

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