Who certifies scuba divers.

The agencies at a glance

Founding details below are each organisation's own account unless another source is named. Where sources disagree, both versions follow the table.

BSAC

BSAC's milestones page says Oscar Gugen and Peter Small founded the club at an inaugural meeting at the Waldorf Hotel in London on 15 October 1953, and that its first branch, London No. 1, formed on 4 May 1954. BSAC's own accounts of that first meeting differ: the milestones page says 100 divers attended, while its 70th-anniversary article says 22 enthusiasts formed the first branch. The two figures may count different things. BSAC says membership grew from 100 to more than 1,100 by 1955 and reached 13,000 in 1969. It introduced new diver grades in 1984, including Novice, now called Ocean Diver.

NAUI

NAUI's heritage page says that in 1959 the National Diving Patrol was renamed the National Association of Underwater Instructors, and that its first major Instructor Certification Course was held in Houston, Texas in 1960. It names Al Tillman and Neal Hess among the first directors. The founding year is given differently: Wikipedia (secondary) gives 1959 as the founding date and 1960 as the formation date, while a NAUI press release, seen only in a search summary, says NAUI incorporated in California in 1960 as a not-for-profit educational association. The 1960 course is also counted two ways. The heritage page says it certified 72 candidates; the press release, again seen only in a search summary, says 72 attended and 53 graduated. We could not confirm the press release wording.

CMAS

Wikipedia (secondary) says CMAS was set up at a meeting in Monaco in January 1959, after a congress of diving federations in Brussels in September 1958, and succeeded an underwater sports committee founded in 1952. It has sport, technical and scientific committees and is listed as recognised by the International Olympic Committee as the international federation for underwater sport. The same Wikipedia article gives its size two ways: 105 nations as of February 2024, and at least 130 national federations. Its diver grades use a star system, and Wikipedia notes that some national CMAS federations set their own limits for them. CMAS is not part of the WRSTC councils described below. No primary CMAS page surfaced in our research, so CMAS facts here rest on Wikipedia.

PADI

PADI's history page says John Cronin and Ralph Erickson founded it in 1966 after meeting at Erickson's apartment in Morton Grove, Illinois. Wikipedia (secondary) adds that Cronin had been a NAUI instructor and wanted modular courses rather than one universal course. PADI says it introduced its first advanced and speciality programmes in 1967, launched Open Water Diver in 1972, and became the world's leading scuba training organisation in the late 1980s; those are PADI's own claims. It marked its 50th anniversary in 2016.

SSI

SSI says it was established in 1970. Wikipedia (secondary) names Robert (Bob) Clark as founder, with several others, and says SSI merged with the National Association of Scuba Diving Schools in 1999 and was acquired by HEAD, owner of the Mares equipment brand, on 1 January 2014. SSI's 2026 site footer shows HEAD Watersports. SSI lists programmes it aligns with ISO standards, including ISO 24801 parts 1 to 3.

SDI and TDI

TDI's story page says TDI was founded in 1994 and that SDI followed in 1998 as its sport diving division; TDI's profile of Bret Gilliam says SDI came after TDI instructors asked for an entry-level programme. The same group created ERDI for public safety diving and PFI for freediving in 2000. The founding details are disputed. TDI's own Gilliam profile says he formed TDI in 1994 and names no co-founders. Wikipedia (secondary) gives 1993, and Divernet dates the parent company, International Training Inc, to 1992. Search summaries of TDI's site name David Sipperly as a co-founder, while Wikipedia and Divernet name Tanya Burnett; we could not confirm either from a primary page.

GUE

InDepth, GUE's own magazine, says Jarrod Jablonski launched GUE as a not-for-profit on 1 July 1998 with seven courses in cave, technical and rebreather diving, and that it moved into its own building in High Springs, Florida in 2005. Wikipedia (secondary) associates GUE with the "Doing It Right" (DIR) approach and the Hogarthian equipment configuration. GUE now also runs recreational courses from an entry level up.

RAID

Wikipedia (secondary) says RAID was founded in 2007 to train divers on the Poseidon Mk VI Discovery rebreather and later added open circuit, recreational, technical, snorkelling and freediving courses. Its country of origin is unsettled: Divers24 says Sweden and X-Ray Magazine says Australia, both seen only in search summaries.

The training councils

The World Recreational Scuba Training Council (WRSTC) says it was founded in 1999 and that its main goal is worldwide minimum training standards. Its members are regional councils, each made up of training organisations that together account for at least half of the annual diver certifications in their country or region. It lists four: Canada, Japan, the United States and Europe. Member councils must make sure their members meet or exceed WRSTC standards.

Wikipedia (secondary) says the US council (RSTC) was created in 1986 and lists its 2025 members as IANTD, NAUI, PADI, PDIC, SDI, SEI, SSI, SNSI, RAID and NASE. It lists ACUC Canada, PADI Canada and SDI North America for RSTC Canada, and says RSTC Europe includes PADI EMEA, SSI Europe and DAN Europe among others. How the councils and ISO standards fit together is on ISO diver standards.