n 1967, Doxa introduced the pioneering Sub concept, heralded as the first truly ’mainstream’ professional diving watch. Its groundbreaking, radical innovations quickly established it as a benchmark for professionals as well. Water-resistant to 30 ATM (or 300 meters), this watch was the first to feature a unidirectional rotating bezel with dual dive time and depth indications to ensure a safe ascent without the need for decompression stops.

At the time, divers relied on the US Navy’s no-decompression dive tables as their golden standard for determining how much time they could spend at a given depth and return to the surface without the risk of decompression sickness. Doxa engineers succeeded in integrating the US Navy’s values into the bezel, in orange on an outer ‘depth’ ring, and in black on an inner ‘minutes’ ring – a Doxa patent.

The Sub would become a legend, easily recognisable because of its bright orange dial – a first for a diver’s watch, contrasting with the traditional black or white dials of the time. From 1968 onwards, millions of television viewers could hardly miss the Sub 300 on the wrists of the divers slipping into the sea from the deck of the Calypso and taking them on fascinating missions to explore ’The Undersea World of Jacques Cousteau.’ Captain Jacques-Yves Cousteau – who co-invented the Aqua-Lung, the first self-contained underwater breathing apparatus, and is considered the father of modern scuba diving – liked the Sub 300 so much that he acquired the exclusive distribution rights for the USA.

Another first: In 1969, Doxa introduced the helium release valve (HRV) on the Sub 300T Conquistador. The HRV is designed for the most technical type of underwater activity at depths greater than what is possible using standard scuba gear: saturation diving. Here, divers operate from a diving bell in which they breathe a special mixture, usually 20% oxygen/80% helium (heliox), to prevent the risks associated with nitrogen. Helium molecules are the second-smallest found in nature and even water-tight seals can’t stop them from getting inside a watch. During decompression, as the diving bell ascends back to the surface, the helium expands and gets trapped inside the watch. The one-way HRV allows the helium particles to escape without ever compromising the watch’s waterproofness. Without it, the pressure build-up would damage to the watch and cause the crystal to literally pop off.

Based on the concept that a sports watch should excel in every scenario, the Sub 300β retains all of its foundational tool watch features while embracing style and elegance. Keeping to the 42.5 mm diameter, Doxa has subtly modified the case design to slim down the profile to just 11.95 mm (compared to the Sub 300T’s 13.65 mm) and reduced the bezel height by 0.5 mm.

The result is a model with lighter, more contemporary proportions: while the stainless steel case maintains the watch’s functional integrity, the black ceramic bezel and a screw-down crown affirm its sport-chic character. The dial’s sophisticated sunburst finish and understated wave motif play with the light, creating a radiant backdrop for the essential information provided by the hands, hour markers and date.

The watch is fitted with an FKM rubber strap in the dial’s color or in white (for the Caribbean and Searambler references). Also available on request is the historic stainless-steel “rice grain” bracelet. Both options come with a deployant clasp featuring a wetsuit extension and the iconic “Doxa Fish” symbol.

Water-resistant to 30 ATM, or approximately 300 meters, the watch is engineered for exploring the seabed in complete safety, its scratch-resistant sapphire crystal is anti-reflective, and the Swiss automatic movement – with Doxa decorations – offers a power reserve of around 38 hours.

True to the Doxa’s ethos of defying convention and always pushing the boundaries, the Sub 300β is a diver that captures the spirit of the times, while cultivating an elegant, modern sport-chic look for the city.

TECHNICAL SPECIFICATIONS

Indications

• hours, minutes, seconds, date

Case

• 316L Stainless steel
• Diameter: 42.50 mm x 44.50 mm
• Height: 11.95 mm
• Helium release valve
• Crystal: ‘Flat’ sapphire with anti-reflective coating
• Screw-in steel caseback
• Black ceramic screw-down crown
• Width between lugs: 20 mm
• Water-resistance: 300 meters, equivalent to 30 ATM, approximately 980 feet

Dial

• Sunburst finish with wave pattern
• Coloured hands, orange or tone-on-tone, highlighted with Super-LumiNova
• Outer minute track, painted, glossy black

Bezel

• Black ceramic bezel
• Unidirectional rotation
• Outer ring: Depth in feet (black tone-on-tone indications), Super-LumiNova dot at 12 o’clock
• Inner ring: Duration in minutes (black tone-on-tone indications)

Movement

• Swiss mechanical movement, self-winding, 3 hands
• Power reserve: 38 hours
• Frequency: 28,800 vph (4 Hz)
• Doxa decorations

Strap/Bracelet

• FKM rubber strap, tone-on-tone matching the dial (or white for ‘Caribbean’ and ‘Searambler’); black PVD-coated folding clasp with ratcheting wetsuit extension, ‘Doxa fish’ symbol
• Or, 316L stainless steel ‘beads of rice’ bracelet; stainless steel folding clasp with ratcheting wetsuit extension, ‘Doxa fish’ symbol

Retail price

• With stainless steel bracelet: CHF 2,190.00 / EUR 2,450.00 / USD 2,290.00
• With rubber strap: CHF 2,150.00 / EUR 2,410.00 / USD 2,250.00