This club was formed by a group of divers in London back in 1953. BSAC was a founding member of the Confederation Mondiale des Activities Subaquatiques. The BSAC school system is now taught in over 200 schools through out the world. It is also considered to be the world's largest dive club.

CMAS was created in 1959 to unite all the national diving organizations that were beginning to develop worldwide. Jacques Cousteau was the organisation's first president and the organisation now certifies over a hundred thousand divers every year.

This Californian based agency is considered to be the world's largest diver-training organisation. The PADI training system is offered in over 3000 dive centres and resorts throughout the world. The schooling system incorporates learning via written and video modules, confined water training, a written exam and four open water dives.

NAUI, also based in the United States of America, offers a worldwide diver training certification programme for use by professional diving instructors. It is owned and operated as a non-profit association.

SSI, the company promoting "serious diving - serious fun", is Colorado based. The first SSI agency was opened in Southeast Asia in 1983 and now has a worldwide network of regional centres serving the needs of divers, instructors and dealers. SSI merged with the National Association of Scuba Diving Schools in 1999.