For years, I scuba dived and taught diving all over the world with my trusty Suunto Mosquito dive computer and apart from a battery change, it never let me down, until it did when it sank into the deep when the watch clasp and lanyard it was attached to both failed at the same time (it does happen!). So I was eager to try the new waterproof Garmin Descent MK3i which is not only a dive computer but also a smart watch too, with a huge array of lifestyle activity and healthy wellbeing customisable settings to suit individual needs.

There are so many options that the setup took a while for me, with a bit of headscratching and referring to the manual along the way, but that is to be expected with any new tech. A quick setup guide which comes with the watch could be a useful future addition.

The digital compass allows you to navigate with ease

I downloaded the Garmin Dive app to my Android smartphone, and, after connecting the watch via Bluetooth, found this a great feature for logging my dives. The watch is not too bulky on the wrist and is comfortable to wear, even over a thickish wetsuit, and it is easy enough to attach a lanyard as backup in case the strap fails.

When performing a safety stop, the time is highlighted in green, making it easy to monitor

I tested the watch while diving in the Red Sea in Egypt with two friends. Firstly, this watch has everything you could possibly need as a recreational scuba diver – gas mix setting (nitrox and trimix) so you can set the mix you are diving with to get the right no decompression time, 3-AXIS compass, LED flashlight, which includes a strobe, which is useful for an emergency or attracting attention on the surface, as well as GPS to mark your entry and exit points and dive planner (no decompression limit and gas deco).

The numbers can be made bigger, so you can easily read your depth, no decompression time etc, and the sapphire crystal AMOLED screen is bright, crisp and clear underwater. The dive function button is more prominent than the rest of the watch buttons, so it is easy to locate.

The Garmin Descent T2 transceiver syncs to the Mk3i. It is screwed into the top of the regulator, allowing you to monitor your tank pressure. If you dive buddy has a T2, you can also sync to monitor their air too

It is compatible with the Garmin Descent T2, a transceiver which can be screwed into the top of your regulator and transmits tank pressure, air time etc. This is a great feature for instructors or those guiding. You can also pair with your dive buddy (if they also have a Garmin Descent) and even send each other short pre-formatted messages (again, very useful if you were guiding, instructing or diving with someone inexperienced).

Underwater, the touchscreen was responsive, although as I was diving in warm water, I didn’t test it with gloves on. A veriometer is built into the watch, and this worked well when I had to chase after my buddy a short distance when she began ascending too quickly during a safety stop. The ascent alarm has a decent pitch and level, although I would prefer it to be a bit louder. You can also set it to vibrate rather than an audible alarm (although the watch would need skin contact for this to work effectively).

The battery life really is incredible, and I didn’t need to charge it at all during the five days I was in Egypt. The only annoying feature was that if I wore the watch when jumping into the sea or pool, it could sometimes record this as a mini dive. This has been rectified since my test, and a new auto dive snooze feature has been introduced to prevent this from happening.

Check out our full guide to the very best waterproof Garmin watches.