Recreational diver training is the process of developing skills and knowledge in the use of diving equipment and techniques so that the diver is able to dive with minimum risks.
Not only is the underwater environment hazardous but diving equipment can be dangerous, there are unexpected problems that divers must learn to avoid. Divers need practice and a gradual increase in challenge to build their confidence in their equipment and themselves, to develop the skills needed to control the equipment and to respond properly if they encounter difficulties.
Most commercial operators and dive clubs serving divers insist that each diver is able to show them "certification", for the type of diving the diver intends to do. Dive operators, dive shops, and compressor operators on occasion have been known to refuse to allow uncertified people to dive, hire diving equipment or have their diving cylinders filled.
Many diver training organizations exist, throughout the world, offering diver training leading to certification: the issuing of a "Diving Certification Card," also known as a "C-card," or qualification card.
Diving instructors affiliated to a diving certification agency may work independently or through a university, a dive club, a dive school or a dive shop. They will offer courses that should meet, or exceed, the standards of the certification organization that will certify the divers attending the course.
Reliable and unbiased advice on how to find quality diving instruction can be difficult to come by. There are computer bulletin boards such as ScubaBoard that, at their best provide sterling advice: "How to find an excellent SCUBA class," but that at their worst can be misleading.
Recreational diver training courses range from minor specialties which require one classroom session and an open water dive, and which may be completed in a day, to complex specialties which may take several days to weeks, and require several classroom sessions, confined water skills training and practice, and a substantial number of open-water dives, followed by rigorous assessment of knowledge and skills. Details on the approximate duration of training can be found on the websites of most certification agencies, but accurate schedules are generally only available from the specific school or instructor who will present that course, as this will depend on the local conditions and other constraints.