CMAS (Confédération Mondiale des Activités Subaquatiques)

The World Underwater Federation, founded in 1959 with Jacques-Yves Cousteau as first president, known for its one, two, and three star diver grades.

CMAS, the Confédération Mondiale des Activités Subaquatiques or World Underwater Federation, is an international umbrella organization for diving founded in Monaco in 1959, with Jacques-Yves Cousteau as its first president. Rather than certifying divers directly everywhere, CMAS sets standards that national federations, such as FFESSM in France or FIPSAS in Italy, deliver through local clubs and schools rather than commercial resort operations.

CMAS is best known for its star system. Recreational divers progress through One Star, Two Star, and Three Star Diver grades, and instructors through One to Three Star Instructor ratings. A CMAS One Star Diver corresponds roughly to Open Water Diver level at other agencies, while Two and Three Star divers are trained for greater depth, autonomy, and dive leadership. Training under CMAS federations is often club based, spread over months, and traditionally strong on theory and watermanship.

CMAS cards are recognized worldwide, though outside Europe you may occasionally need to explain the star equivalences to an operator used to PADI or SSI levels. An equivalence table from your federation usually settles the question in seconds. Beyond diver training, CMAS also governs competitive underwater sports, including finswimming, spearfishing, and underwater hockey, and issues scientific diving credentials, a reminder that it is a federation of federations rather than a commercial training company.