Diver training
Recreational diving is taught through a small number of international agencies. Each has its own philosophy, course structure, and footprint — but the cards they issue open the same dive boats. A short guide to the six you’re most likely to meet.
Since 1966
Professional Association of Diving Instructors
Rancho Santa Margarita, California, USA
The largest recreational diver training organisation in the world, with a network of more than 6,600 dive centres and over 128,000 individual professionals operating in 186 countries. PADI is built around a commercial, dive-shop-based model and a tightly standardised, modular course progression from Open Water through Divemaster and Instructor.
Visit padi.comSince 1970
Scuba Schools International
Wendelstein, Bavaria, Germany
The second-largest recreational training agency by volume, now owned by the Head sporting-goods group. SSI delivers its curriculum through a digital-first learning platform and a network of authorised dive centres and resorts, with a strong presence in Europe and Asia-Pacific.
Visit divessi.comSince 1959
National Association of Underwater Instructors
Riverview, Florida, USA
The oldest of the US-based recreational training agencies and structured as a non-profit. NAUI publishes course standards but gives instructors meaningful discretion over how those standards are met, a model that has earned it long-standing relationships with military, scientific, and public-safety diving programmes.
Visit naui.orgSince 1998
Scuba Diving International
Stuart, Florida, USA
The recreational sister agency to Technical Diving International (TDI), launched in 1998 to bring TDI's technical-diving methodology into mainstream sport diving. SDI sits inside the International Training family alongside TDI (technical), ERDI (public-safety), and PFI (freediving) — a one-stop path for divers who plan to progress beyond recreational limits.
Visit tdisdi.comSince 1953
British Sub-Aqua Club
Ellesmere Port, Cheshire, United Kingdom
The National Governing Body for scuba diving and snorkelling in the United Kingdom, and one of the oldest recreational diving organisations in existence. Unlike most agencies, BSAC operates on a club-and-branch volunteer model rather than a commercial dive-shop model — divers train and progress through their local branch — and its certifications are recognised worldwide.
Visit bsac.comSince 1959
Confédération Mondiale des Activités Subaquatiques
Rome, Italy
Founded in Monaco in 1959, the World Underwater Federation is an international umbrella of national diving federations rather than a direct training organisation. CMAS standardises a star-rated certification system (1-star, 2-star, 3-star diver) issued through its national member federations, and also governs competitive underwater sports such as finswimming and underwater orienteering.
Visit cmas.orgAgency names and trademarks are the property of their respective owners.