Doxa introduced the SUB 300 in 1967 as a purpose-built dive watch aimed at ordinary sport divers rather than only professional units. The case is a cushion-shaped block of stainless steel — the modern reissue measures 42.5 mm and 20 mm between the lugs — rated to 30 bar, roughly 300 metres. Its most consequential feature is the bezel: a patented unidirectional rotating ring carrying two scales at once, depth and dive time, so a diver can read the no-decompression limit for the planned depth and then track the elapsed minutes against it. The bracelet Doxa fitted, the “beads of rice”, became almost as recognisable as the dial.

The orange dial was chosen after testing legibility underwater, work Doxa carried out on Lake Neuchâtel with Claude Wesly of Cousteau’s team, because orange stays readable longest as light falls off with depth. That colour, named Professional, became the brand’s signature, and Doxa sold the SUB 300 in the United States through Cousteau’s US Divers organisation, which tied the watch to the era’s most famous diving expeditions. A black-dial version, the Sharkhunter, and later yellow, silver and blue variants followed, each with its own name.

From 1969 to 1979 the SUB 300 served as the official watch of Switzerland’s elite army diving troops, a credential Doxa still cites. The model was discontinued and the company changed hands, but its reputation survived in print: Clive Cussler put a Doxa on his hero Dirk Pitt across the novels, and collectors kept the orange-dial Subs in demand. Doxa marked the 50th anniversary in 2016 with a sold-out reissue and relaunched the SUB 300 as a permanent collection piece, now certified as a chronometer and still built around the same case, bezel and colour logic as the 1967 original.