A scuba diver wears an air tank and dives in a body of water, usually to explore underwater ship wrecks or natural wonders like the reef. Scuba diving allows you to explore much deeper than snorkelling without relying on surface oxygen, and is often done as a recreational sport, hobby, or exercise.

The most common scuba diving emergency is running out of breathing gas under water, also called an out-of-air incident. This is a life threatening situation because without a source of breathing gas divers die within minutes. If this happens, a diver can either reach the surface and breathe normal air pressure, or use an alternative scuba supply (called a bailout scuba), which does not require a buddy.

Some scuba divers work for commercial companies in the field of underwater exploration, such as oil or gas pipeline inspection and maintenance. Since these are considered jobs, scuba diving is covered under labor standards and regulations, including OSHA in the United States.

Many scuba divers enjoy the underwater world for its aesthetic appeal, natural beauty and fascinating creatures. Others find the practice to be a healthy, calming and spiritual experience that builds strength and endurance. The physical benefits of scuba diving are similar to those of jogging and other aerobic exercises, but with the added benefit of an exotic setting and a meditative state of mind. As a recreational activity, scuba diving is the perfect way to get some fresh air, escape from daily stresses and see the underwater world with new eyes.