In 1952, two French military officers, Captain "Bob" Maloubier and his lieutenant Claude Riffaud were tasked by the French Military of Defence to create the elite combat diving unit "Les Nageurs de Combat".

The new unit required rugged, water-resistance and reliable material capable of withstanding the testing conditions of underwater missions. The two officers’ attempts to find an existing watch that could meet these requirements were fruitless, and their search led them to Blancpain.

Working closely together, the company's leading engineers and watchmakers successfully developed the Fifty Fathoms in 1953. The operational needs of the Les Nageurs de Combat were met, and the archetypal diver's watch was born

Utilizing an automatic winding movement for robustness, and a unidirectional bezel to keep track of elapsed diving time (a world's first), the Fifty Fathoms was cased in robust stainless steel. Its guaranteed water resistance was a then-unheard-of fifty fathoms or 91.45 meters, which was the maximum dive depth for a diver equipped with cylinders containing a mix of oxygen and nitrogen.

Since then the Fifty Fathoms has served with distinction in the US Navy Seals, the German Bundesmarine as well as the armed forces of France and Israel.

Marine exploration organizations, like the GERS in France, also adopted the Fifty Fathoms as their timekeeping instrument of choice. Notably, the Fifty Fathoms was used by the film crew of The Silent World, the Palme d'Or and Oscar winning production of Jacques Cousteau and Louis Malle.