Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.
A divemaster (DM) is a role that includes organising and leading recreational dives, particularly in a professional capacity, and is a qualification used in many parts of the world in recreational scuba diving for a diver who has supervisory responsibility for a group of divers and as a dive guide. As well as being a generic term, 'Divemaster' is the title of the first professional rating of many training agencies, such as PADI, SSI, SDI, NASE, except NAUI, which rates a NAUI Divemaster under a NAUI Instructor but above a NAUI Assistant Instructor. The divemaster certification is generally equivalent to the requirements of ISO 24801-3 Dive Leader.
The National Association of Underwater Instructors is a nonprofit association of scuba instructors founded in 1960 by Albert Tillman and Neal Hess.
Mandy-Rae Cruickshank is a world champion free-diver and record-holder from Vancouver, British Columbia.
Scuba Schools International (SSI) is a for-profit organization that teaches the skills involved in scuba diving and freediving, and supports dive businesses and resorts. SSI has over 3,500 authorized dealers, 35 regional centers, and offices all over the world.
Solo diving is the practice of self-sufficient underwater diving without a "dive buddy", particularly with reference to scuba diving, but the term is also applied to freediving. Professionally, solo diving has always been an option which depends on operational requirements and risk assessment. Surface supplied diving and atmospheric suit diving are commonly single diver underwater activities but are accompanied by an on-surface support team dedicated to the safety of the diver, including a stand-by diver, and are not considered solo diving in this sense.
Martin Štěpánek is a world class freediver and record-holder.
Scuba Diving International (SDI) is a Scuba training and certification agency. It is the recreational arm of Technical Diving International, a technical diver training organization.
Technical Diving International (TDI) claims to be the largest technical diving certification agency in the world, and one of the first agencies to offer mixed gas and rebreather training. TDI specializes in more advanced Scuba diving techniques, particularly diving with rebreathers and use of breathing gases such as trimix and heliox.
The World Recreational Scuba Training Council (WRSTC) was founded in 1999 and is dedicated to creating minimum recreational diving training standards for the various recreational scuba diving certification agencies across the world. The WRSTC restricts its membership to national or regional councils. These councils consist of individual training organizations who collectively represent at least 50% of the annual diver certifications in the member council's country or region. A national council is referred to as a RSTC.
Master Scuba Diver (MSD) is a scuba diving certification or recognition level offered by several North American diver training agencies, such as the National Association of Underwater Instructors (NAUI), the Professional Association of Diving Instructors (PADI), Scuba Diving International (SDI), and Scuba Schools International (SSI). Other agencies offer similar programs under other names, such as "Elite Diver". Each of these agencies touts their program at this level as the highest, non-leadership program.
Steve Lewis is an active cave and wreck diver. Born in Peckham, New Cross London, he currently resides in Muskoka, Ontario Canada.
Bret Clifton Gilliam was an American pioneering technical diver. He was most famous as co-founder of the certification agency Technical Diving International along with Mitch Skaggs, and as the one time holder of the world record for deep diving on air. He is also one of diving's most popular writers. Gilliam is the author or coauthor of 72 books, over 1500 feature magazine articles, and over 100 magazine cover photos. In his diving career he has logged over 19,000 dives since 1959.
Diver training is the set of processes through which a person learns the necessary and desirable skills to safely dive underwater within the scope of the diver training standard relevant to the specific training programme. Most diver training follows procedures and schedules laid down in the associated training standard, in a formal training programme, and includes relevant foundational knowledge of the underlying theory, including some basic physics, physiology and environmental information, practical skills training in the selection and safe use of the associated equipment in the specified underwater environment, and assessment of the required skills and knowledge deemed necessary by the certification agency to allow the newly certified diver to dive within the specified range of conditions at an acceptable level of risk. Recognition of prior learning is allowed in some training standards.
Emergency Response Diving International claims to be the largest organization devoted to training emergency response divers in public safety diving (PSD). It was founded in Orlando, Florida in 2000 by Scuba Diving International in response to a high accident rate in the training of emergency response divers. The earliest lessons held by it were attended by almost 24 police officers, firefighters, and volunteers from the United States. Mitch Skaggs was one of the instructors at the founding of the organization.
Dive RAID International is a dive training organization which was founded in 2007 to support diver training for the Poseidon Mk VI Discovery Rebreather. It has since extended its scope to include open circuit scuba training and training for both recreational and technical diving sectors as well as snorkeling and freediving.
Richard Collett is a freediver and national record holder for the Cayman Islands in the sport of freediving. Collett started his training in apnea and freediving in August 2016 with the goal of being the first Caymanian to set and hold national records in all competitive freediving disciplines.
The following outline is provided as an overview of and topical guide to underwater diving:
This is a list of underwater divers whose exploits have made them notable. Underwater divers are people who take part in underwater diving activities – Underwater diving is practiced as part of an occupation, or for recreation, where the practitioner submerges below the surface of the water or other liquid for a period which may range between seconds to order of a day at a time, either exposed to the ambient pressure or isolated by a pressure resistant suit, to interact with the underwater environment for pleasure, competitive sport, or as a means to reach a work site for profit or in the pursuit of knowledge, and may use no equipment at all, or a wide range of equipment which may include breathing apparatus, environmental protective clothing, aids to vision, communication, propulsion, maneuverability, buoyancy and safety equipment, and tools for the task at hand.
United States 
