PADI stands for the 'Professional Association of Diving Instructors'. Established in 1966 in the USA, they are now the largest diving assocation, with over 5000 dive centres in 180 countries, including a strong presence in Asia. They offer training in recreational diving from entry level upwards, starting with the Open Water Course - a 3-4 day course of 5 pool sessions and 4 open water dives, awarding a licence to dive to a depth of 18m.
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SSI stands for 'Scuba Schools International'. They were formed back in 1970 in the USA and have now expanded to have over 2000 dive centres in over 90 countries worldwide. They offer training in recreational diving from entry level upwards, starting with the Open Water certification - a 3-4 day course of 6 pool sessions and 5 open water dives, awarding a licence to dive to a depth of 18m.
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CMAS, or the 'Confédération Mondiale des Activités Subaquatiques' was founded in Brussels in 1958, making it one of the most established diving associations. CMAS operates through an international framework of national diving associations that subscribe to CMAS standards, such as the Thailand Diving Association, the Philippine Federation of Underwater CMAS Activities and the Malayan Subaqua Club. Certifications are based on a star system from 1 star to 3 stars. The entry level qualification requires a minimum of 5 scuba dives and 14 hours in-water training, awarding a licence to dive to a depth of 18m.
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Formed just a year after CMAS, the 'National Association of Underwater Instructors' is a non-profit American Diving Association who also operate internationally. Highly respected, they offer a range of courses from entry level through to instructor, plus a wide range of technical diving courses. Their entry level diving qualification is known as 'Scuba Diver' and consists of 10 hours confined or pool training and a total of 4 open water dives, awarding a licence to dive to a depth of 18m.
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BSAC stands for the British Sub Aqua Club. Founded in 1953, it is the oldest diving association. While primarily UK based, it has a small presence in Asia, with national associations in China, Japan & Korea. The entry level qualification is called 'Ocean Diver' and consists of 5 pool or confined water sessions and 5 open water dives, awarding a licence to dive to 20m.
Visit BSAC's website