SCUBA, meaning self contained underwater breathing apparatus, is a form of underwater diving where rather than breath hold a scuba diver takes down a tank of compressed air and a set of underwater equipment to use this air. There are several different disciplines in the industry, such as recreational scuba diving, technical diving, commercial diving and military diving.
Scuba diving separates itself from swimming and other forms of diving as a diver breathes continuously. Other factors come into it as well, as unlike in swimming a diver wants to be streamlined, propelling themselves only to swim forwards. This is why unlike in all other sports, buoyancy is a key theme in scuba diving. Buoyancy, or neutral buoyancy, is the idea of maintaining a hover throughout a dive and not using fins or arm movements to maintain position. For this reason divers usually wear a buoyancy compensator (BC), also known as a Buoyancy Control Device (BCD), which is a jacket that can be inflated and deflated with air to maintain neutral buoyancy during a dive.
The Recreational Scuba Diving industry is dominated by two main training federations, Professional Association of Diving Instructors (PADI) and the British Sub Aqua Club (BSAC), which outline all their training standards in line with international law. PADI certifies diving centres and diving professionals to carry out training of PADI Courses. A full description of PADI courses is available at at Dive The Gap. Scuba Divning courses are designed to take you from beginner levels as far as you want to go.