As the world looked up at the stars above, another universe beckoned from below: the glistening, deep-blue sea. People are fascinated by what is under the ocean’s surface. We love to be tantalized by underwater movie adventures, engrossed by TV shows and documentaries, transfixed by magazine articles.

An exciting new world of sports and adventure beneath the waves was made possible by the invention of the Aqua-Lung underwater breathing regulator during World War II. Urs Eschle was head of product development at DOXA at this time and pursued a vision to bring precision watchmaking to divers. Urs had the same innovative sparkle that DOXA’s founder Georges Ducommun had shown half a century before when he designed the “8-Day DOXA Caliber” for an automobile industry gaining momentum.


A reliable and robust watch is essential underwater equipment. Although diving watches had been around for a decade they mostly had the look and feel of a military or professional tool. And they were expensive. Urs saw the need for an affordable, dependable, purpose-designed watch for the growing community of underwater explorers. He set up a team that included professional divers like legend Claude Wesly and inventor of the Aqua-Lung Jacques-Yves Cousteau.


A team with a mission
Divers depend on their watch for safety and so Urs wanted to design a watch that was more than just attractive, affordable and watertight. And so it was with a true sense of mission that Project SUB got underway in 1964. His research was helped by the fact one of the members, Claude Wesly, had been one of the first two “aquanauts” of the pioneering “Précontinent I, II, and III” dive missions that studied life in an underwater habitat. 

Getting to the core of a true diver’s watch
It would have been easy to simply tweak established diving watch characteristics – a black dial, hard to miss indices, fat luminescent hands, a rotating bezel and a heavy-duty strap. But DOXA doesn’t do easy. Every aspect of what makes up a true diver’s watch was explored, examined and thought through until the optimum solution was found.

Size and substance

The first SUB iteration went beyond the typical size of other diving watch cases available at the time. The 45 mm diameter allowed for easier underwater handling and accommodated a larger dial for greater visibility. The case is crafted from a single block of stainless steel guaranteeing absolute watertightness tested to a depth of 300 meters (1000 feet). These features became the DOXA SUB 300 platform.

Orange is the new dial
The team asked a simple question:“Does a black dial underwater make the most sense?” To answer this question the team’s engineers investigated the physics of light underwater.  Divers were sent down to various depths in Lake Neuchatel nearby and practically every color of the rainbow was tested. After countless dives there was one clear winner for the range in which most sports divers operate: bright orange. It became a signature trait and the orange of a DOXA SUB is hard to miss, above and below the surface.

An intelligent – and safer – bezel
To dive safely, it is essential to know exactly how long you can stay underwater without a decompression stop when surfacing. Where other teams stopped at a unidirectional bezel, the DOXA team leapt further. DOXA incorporated the US Navy’s no-decompression limit table – the reference for diver safety. The SUB’s patented bezel has two separate scales to reliably calculate and monitor dive times: orange for the outer ‘depth’ ring, and black for the inner ‘minute’ ring.

Hours are secondary underwater
The pros on Project SUB saw beauty in functionality over symmetry. They knew divers need time counts in minutes and seconds underwater and need that information available at glance without distraction. Upon reflection, the Project SUB team agreed the hour hand took up valuable real estate on a diver watch dial. It made more sense to have a larger minute hand with an easy to spot second hand to check time with the twist of a wrist – not the cock of your elbow. 

An appreciation for comfort and practicality
DOXA’s engineers gave diver needs precedence and came up with another first to keep things simple. They preserved the elegance of a metal bracelet but added an innovative flex buckle. This flex meant the SUB’s bracelet could fit around a wetsuit sleeve without readjusting the watch or fiddling with the links before a dive. The bracelet also featured a unique ratchet mechanism built into the clasp so it could be sized without having to add or remove links.


The DOXA SUB 300T made quite a debut splash at Baselworld in 1967. The first 100% purpose-designed, professional-grade sports diving watch was launched after three years of intense research and development. The radical innovations of the DOXA SUB 300T soon established it as the professional benchmark. The SUB 300T watch got its name as it was water resistant to 300 meters (1000 feet) and luminous material on the hands and dial was made from tritium. 

The Cousteau Connection
Jacques-Yves Cousteau was the Aqua-Lung co-inventor and a diving legend in his own time. He liked the DOXA SUB concept so much he negotiated an exclusive distributorship for his US Divers company. The orange dial became a familiar sight on “Calypso” diver wrists from 1968, accompanying millions of TV viewers on weekly missions to explore “The Undersea World of Jacques Cousteau” – a touchstone for underwater documentaries still today. 

The SUB concept, perfected: Conquistador.
In 1968, Urs and his team conquered the final frontier: The SUB 300T Conquistador was the first diving watch to feature a helium release valve (HRV). Divers inhale an air-helium-hydrogen mix when they use a decompression chamber. Previously, the helium molecules in this decompression mix penetrated watch case seals and a sudden pressure differential caused the crystal to explode. The HRV let the helium out while preventing water ingress. The Conquistador is one of the most sought-after vintage diver’s watches ever.

Passing the test of time
DOXA SUB represents the diving watch benchmark across generations of divers and adventurers the world over. The watches have greatly contributed to sport and professional diver safety thanks to the many technical innovations they introduced. DOXA remains true to the spirit of adventure as the proud sponsor of Mission 31, a project initiated in 2014 by Jacques-Yves’ grandson Fabien Cousteau. “Aquarius” is the world’s only underwater marine lab in the Florida Keys National Marine Sanctuary. The lab set an ocean exploration submersion record of 31 consecutive days. The team’s feat is honored with a limited edition collection of 331 special timepieces featuring the famous orange dial.