This new Citizen Promaster Eco-Drive Dive watch has a year-long power reserve

If there’s one thing I love about Citizen, it’s their dedication to making rugged, go-anywhere watches that don’t need mollycoddling. Their latest, the Citizen Promaster Eco-Drive Professional Diver 300m, continues that tradition with a solar-powered movement that keeps ticking for a full year on a single charge. Yes, 365 days – without ever seeing a sliver of sunlight.

That’s thanks to the Cal. E365 movement, a technological marvel designed to withstand the darkest, deepest dives while still running like clockwork.

With a water resistance of 300 metres and a helium escape valve, this beast of a watch is built for saturation divers. And, although most watches like this rarely venture into the deep, I think this one stands a better chance of reaching the Mariana Trench than many of its luxury dive watch counterparts.

Design-wise, it sticks close to the much-loved BN0156-05E, keeping the signature 4 o’clock crown, beefy indices, and a robust rotating bezel.

The dial – finished in a glossy gradient that subtly darkens towards 6 o’clock – mimics the ocean’s depths, a detail I personally love. At 46mm across and 16.3mm thick, this thing has serious wrist presence, so it’s not for the faint-wristed.

The strap is made from BENEBiOL, a plant-based polyurethane that’s both eco-friendly and resistant to hydrolysis (i.e., it won’t break down when wet). It’s a thoughtful touch that aligns with Citizen’s sustainability efforts.

Flip the watch over, and you’ll find a diving helmet stamped into the case back – a nod to its professional-grade credentials.

At £499 (approx. US$400) and launching in April 2025, this is a serious tool watch with some serious value. A no-fuss, no-battery-change, dive-ready beast that’ll keep going for a year, even if you lock it in a drawer. What’s not to love?

Liked this? Citizen’s Tsuyosa is now available in a more wearable size, making it a perfect entry-level watch

Spencer Hart Buying Guide Editor

About

As Buying Guide Editor, Spencer is responsible for all e-commerce content on Stuff, overseeing buying guides as well as covering deals and new product launches. Spencer has been writing about consumer tech for over eight years. He has worked on some of the biggest publications in the UK, where he covered everything from the emergence of smartwatches to the arrival of self-driving cars. During this time, Spencer has become a seasoned traveller, racking up air miles while travelling around the world reviewing cars, attending product launches, and covering every trade show known to man, from Baselworld and Geneva Motor Show to CES and MWC. While tech remains one of his biggest passions, Spencer also enjoys getting hands-on with the latest luxury watches, trying out new grooming kit, and road-testing all kinds of vehicles, from electric scooters to supercars.

Areas of expertise

Watches, travel, grooming, transport, tech