Every certified diver should own a dive computer. It doesn't need to cost a thousand dollars, and it certainly doesn't need to support technical diving. A straightforward computer costing around $300 can do everything necessary for ordinary recreational dives, provided you know how to use it.
If I have more money to spend, my preference is Shearwater. I like the displays, the interface, the decompression model, and the way the computers are designed around what divers need to see. That's a preference, not a claim that everyone needs an expensive computer. I'd rather see a diver confidently using an inexpensive model than struggling to operate something impressive.
Buy the Display and Controls First
The essential information is straightforward: current depth, elapsed dive time, remaining no-decompression time, ascent rate, and warnings when something needs attention. The computer also needs to account for repetitive dives and support the breathing gases you intend to use. For most recreational divers, that means air and nitrox.
Nearly every modern recreational computer covers those requirements. The real differences become apparent when you try to read the screen, change a setting, or respond to an alert. I want to recognize the important information at a glance rather than remember which page of a menu contains it. I also want buttons I can use with gloves, especially in cold water, and gas settings I can verify before entry without guessing.
I'd handle several models before buying if possible. A bright product photograph tells you little about what the display will look like underwater or whether the buttons are frustrating through thick gloves. Larger wrist computers generally have more room for readable information; watch-style units are attractive for travel and everyday wear. Neither is inherently better, but I'd prioritize underwater usability over appearance.
I also prefer wrist-mounted computers to console-mounted models. Having dive information on my wrist means I can read it without searching for a console, and it doesn't tie the computer to a particular regulator setup. Console computers can work perfectly well; they're simply not how I'd choose to carry critical information.
Decide Which Extras You'll Actually Use
Air integration is the feature I'd be most inclined to pay for. With a compatible transmitter, a computer can show cylinder pressure alongside depth and no-decompression time. Depending on the model, it may also track gas consumption or estimate remaining gas time. I value having that information in one place, so I'd consider an air-integration-capable computer even if I planned to buy the transmitter later.
It remains optional. A conventional pressure gauge is an entirely valid way to monitor gas, and wireless integration doesn't replace a gas plan. If you choose a transmitter, understand what happens when its battery runs down or the connection drops, and how you'll monitor gas if the pressure reading disappears. I've covered the tradeoffs in SPG vs. Air-Integrated Dive Computers.
A digital compass is useful, but not essential to the basic purchase. Wireless logbook downloads, adjustable display layouts, and customizable alerts can all be nice to have. None would persuade me to buy a computer whose primary display or controls I disliked.
Pay attention to the battery, too. Rechargeable computers are convenient when charging is easy. User-replaceable batteries can be especially attractive on longer trips or in remote places, although you still need to understand the manufacturer's replacement and maintenance requirements. I'd consider how and where I dive rather than treating one battery design as universally better.
Understand the Algorithm Without Chasing Longer Bottom Time
A dive computer uses a mathematical model to estimate inert-gas loading and calculate guidance such as no-decompression limits and ascent obligations. Different algorithms and settings can produce different limits for the same dive, particularly across repetitive dives. A computer showing more remaining time isn't necessarily more accurate or safer.
I prefer Bühlmann ZHL-16C with adjustable gradient factors. It's a well-documented approach, and I value being able to understand how the computer arrives at its guidance. That preference is another reason I like Shearwater. But I wouldn't reject a suitable entry-level computer simply because it uses Suunto RGBM or another established model.
For a new recreational diver, the critical skill is understanding what the computer is telling you and staying within the agreed plan. Gradient factors and conservatism settings shouldn't become numbers you change casually to gain a few extra minutes. No decompression algorithm measures your actual tissue loading or eliminates the risk of decompression sickness.
If your buddy's computer gives a shorter no-decompression limit than yours, the team needs a plan that respects the more restrictive limit. Buying a particular algorithm doesn't exempt you from communicating and making conservative decisions together.
Don't Buy Technical Diving Features on Speculation
A computer capable of trimix, multiple decompression gases, and complex technical configurations can work beautifully on a shallow recreational dive. The question is whether those features are worth paying for when you have no plans to use them.
I've made expensive equipment purchases based on what I might do someday, and I wouldn't encourage that approach. If you're diving air or a single nitrox mixture within recreational limits, the basic functions and a clear display matter far more than technical menus you'll never open. If technical training is a serious near-term plan, I'd ask the instructor or program what the computer needs to support before committing to a purchase.
What I'd Actually Buy
If the budget is tight, I'd start with a basic wrist-mounted computer that supports air and nitrox, has a readable screen, and is easy to operate. The Suunto Zoop Novo is an example of that roughly $300 class. Its availability may vary, but a diver doesn't need to move into premium pricing to get capable equipment.
For a dedicated recreational computer with more room in the budget, I'd start with the Shearwater Peregrine TX. Its large display, air-integration capability, digital compass, and Bühlmann algorithm make it a combination I particularly like. The transmitter is an additional purchase, so I'd consider the cost of the complete arrangement rather than only the computer.
For a smaller watch-style computer, I'd look at the Shearwater Tern TX. It offers air integration and a compass in a compact form. Between the Tern TX and Peregrine TX, I'd decide based on how comfortably I can read the screen and whether I want a larger dive-focused display or a smaller device.
For a diver genuinely preparing for technical diving, the Shearwater Perdix 3 deserves consideration, and the Perdix 2 remains a capable option. They offer a larger format, user-replaceable AA batteries, and the technical capabilities that justify their price when you need them. Most recreational divers don't.
A compatible Apple Watch Ultra running a supported dive-computer application such as Oceanic+ is also an option for recreational diving within its operating limits. The built-in Depth app is not a scuba computer. I'd want the owner to understand the application's features, limitations, and subscription requirements, and I wouldn't buy an Apple Watch solely to avoid purchasing a dedicated computer.
A Backup Has to Know Your Dive History
Buying an inexpensive computer first and upgrading later can make sense. The original might become your backup, but only if you treat it as a computer rather than something that lives switched off in the bag.
For repetitive diving, the backup needs the relevant history. It should accompany you throughout the dive series so it can track your exposure, and you need to understand how its algorithm and settings compare with your primary. Turning on an unused computer halfway through a dive vacation doesn't make it an adequate substitute for one that's been recording the dives.
If your primary fails and you don't have a properly functioning backup that has been tracking the same dive history, end the dive safely rather than improvising a replacement. The purchase decision is partly about redundancy, but even more about knowing how to respond when something stops working.
I would rather see someone using one computer they understand completely than carrying two sophisticated computers whose warnings and settings they haven't learned. Buy the features that serve your diving, learn the interface before getting wet, and pay attention to what the computer is actually telling you.