Shearwater Peregrine vs Tern vs Perdix Compared

As a whale shark biologist and underwater photographer, I’ve relied on my dive computer to keep me safe and informed underwater over thousands of dives. My personal favorite are Shearwater computers, so Shearwater computers feature heavily in my Top Dive Computers guide. They’ve earned my, and many other people’s trust over the years.

These three models are the most popular in the Shearwater range, but which one is best for you? Read on, gentle reader, as we dive deep into computer geekdom.

In a nutshell: the Shearwater Perdix is popular amongst tech divers for its big, easy-to-read screen and full tech capabilities. The Shearwater Tern is Shearwater’s compact watch-style computer for sport divers, one you can wear every day. The Shearwater Peregrine takes the recreational features of the Perdix and puts them in an easy to use, affordable, highly capable package. The Peregrine and Tern each come in two versions: a cheaper one, and a TX that adds air integration and a compass.

The latest Shearwater models

Shearwater’s range has changed since we first wrote this comparison, so here’s where each line stands:

• Peregrine TX (2024): the Peregrine TX keeps the Peregrine’s big, easy screen and adds air integration and a digital compass, the two things the original was missing. It’s US$760 from Shearwater, with the transmitter sold separately. The original Peregrine is still sold if you’re happy with a separate pressure gauge. The Peregrine TX is now the top pick in our best dive computers guide.
• Perdix 3: the Perdix 3 has a brighter 2.4-inch colour AMOLED screen, a refined menu layout and still runs on a single AA battery, with air integration from up to four transmitters. It’s US$1,295 from Shearwater. The Perdix 2, which Mads dives and the details below describe, is still sold.
• Tern and Tern TX (2024): Shearwater’s most compact computers, and its cheapest watch-style option. The Tern is the base watch, and the Tern TX adds air integration from up to four tanks and a digital compass. They cover recreational diving and freediving, not tech diving. Shearwater has sold out of a special Limited Edition Tern TX, but the standard models are still available.
• Teric: still sold at US$1,199, and still the only Shearwater watch with trimix and rebreather modes. For most recreational divers who want a watch, the cheaper Tern now makes more sense, so it’s the Tern we compare below.

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Head to head

Shearwater Peregrine vs Tern

Big screen or watch-style? The Peregrine and Tern cost about the same and do the same recreational diving. The Peregrine has the bigger 2.2-inch screen and lasts up to 30 hours of diving. The Tern is a compact watch you can wear every day, with a sharper, brighter 1.3-inch AMOLED screen, a freediving mode and up to 20 hours of diving.

If you want the biggest, easiest-to-read numbers, get the Peregrine. If you’d rather wear your computer every day, get the Tern. Either way, get the TX version if you want air integration and a compass.

Shearwater Peregrine vs Perdix

Simplicity or advanced features? The Peregrine is like the baby brother to the Perdix: great for recreational divers who want a no-fuss computer with a clear screen, and the Peregrine TX now adds air integration. The Perdix adds trimix and rebreather modes, and a battery you swap for any AA. I’m a fan of that battery: charging your computer every night on a dive trip can be a drag.

If you’re fine without tech modes, the Peregrine saves you a fair bit of cash. If you’re heading into technical diving, get the Perdix.

Shearwater Tern vs Perdix

Everyday watch or tech slate? The Tern is a watch for recreational divers and freedivers, at less than half the price of a Perdix 3. The Perdix is built for serious diving, with tech modes, a big screen and an AA battery.

If you want a watch and dive on air or nitrox, the Tern does the job for much less. If you’re heading into technical diving or want the largest screen, get the Perdix. Tech divers who want a watch should look at the Teric, Shearwater’s only watch with tech modes.

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Each Shearwater line in detail

Shearwater Peregrine and Peregrine TX

The Peregrine is by far the most popular Shearwater, because it’s all the Shearwater goodness at a mid-range price. Its 2.2-inch colour screen is bright and easy to read, the two-button menus are simple, and it charges wirelessly, lasting about 30 hours on medium brightness. It handles air, nitrox and three-gas nitrox, supports decompression diving, and won’t lock you out if you miss a stop.

• Peregrine TX: adds air integration (up to four transmitters, sold separately) and a digital compass. It’s our top pick in the best dive computers guide.
• Original Peregrine: no air integration or compass, and US$180 cheaper.
• Things to consider: no freediving mode, it isn’t meant to be worn as a watch, and the battery isn’t user-replaceable.

Read our full Shearwater Peregrine review.

Shearwater Tern and Tern TX

Shearwater’s most compact computer, launched in 2024 and its answer to the watch-style computers from Garmin and others. The Teric was long the recreational diver’s favourite Shearwater watch, even though it was built for tech divers; the Tern is aimed squarely at recreational divers, with most of what made the Teric great, minus the tech modes, for about two-thirds of the price. Its AMOLED display is one of the sharpest on any dive computer, with 15 display colours, an easy switch between dive and watch mode and very easy menus. It charges wirelessly, lasts up to 20 hours of diving and six months on standby, and is rated to 120 m.

• Tern TX: adds air integration from up to four tanks and a tilt-compensated digital compass.
• Tern: the same watch without them, for US$210 less.
• Things to consider: no trimix or rebreather modes, vibration-only alerts, and a toughened glass lens rather than sapphire. It scratches more easily, and Shearwater recommends a screen protector. The battery isn’t user-replaceable.
• Want tech modes in a watch? The Teric adds trimix and rebreather modes, a sapphire lens and longer battery life. Read our Teric review.

Read our full Shearwater Tern review.

Shearwater Perdix 2 and Perdix 3

Loved by tech divers, underwater photographers, and anyone who wants a large screen and air integration (like me!). It’s also popular with older divers whose eyesight isn’t what it was (also like me). The two-button menus work even in a rocking boat, it supports trimix and rebreathers, and one AA battery lasts about 40 to 100 hours of diving depending on the type.

• Perdix 3: the newest model, with a brighter 2.4-inch colour AMOLED screen and a refined menu layout, still on a single AA battery. Mads dives the Perdix 2.
• Perdix 2: still sold, for US$100 less.
• Things to consider: it isn’t designed to be worn as a watch (it comes with a bungee and clips), and you pay for tech features you may never use.

Read my full Shearwater Perdix 2 review.

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Feature Comparison of Shearwater Dive Computers

If you’re like me, you probably have very specific requirements: you don’t want to out-grow your computer for at least a few years. Here’s how the three lines compare, feature by feature.

A few things the table doesn’t show. The Perdix’s AA battery is the one to beat on long trips: carry spares and you never need a charger. The Tern’s AMOLED screen is the sharpest and brightest of the three, but the Peregrine and Perdix 2 fit more on each page. And all three use the same Shearwater menus and Bühlmann algorithm, so moving between them later is easy.

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