Scuba (an acronym for Self-Contained Underwater Breathing Apparatus) diving is a form of underwater diving that allows scuba divers to move more freely than surface-supplied divers. Scuba divers use their own source of breathing gas, usually compressed air or a gas blend with a higher oxygen content (nitrox), which allows them to stay longer underwater than free divers.

Diving with scuba gear requires special training and a number of pieces of equipment. A scuba diver needs a tank to hold their air supply, a dive computer for measuring depth and time underwater, a snorkel for breathing water, fins and a mask for moving through the water, a buoyancy control and weighting system, a dry suit or wetsuit, and other accessories. Professional divers may also use photographic or video equipment, tools for their work, and other specialized equipment.

It is important for all scuba divers to be properly trained, have reliable equipment, and log their dives after each dive. This helps them remember what conditions were like on previous dives, calculate residual inert gases, and plan for future dives.

Scuba equipment is usually made from Neoprene, a chloroprene rubber that is made with butadiene, a fossil fuel-derived chemical. While this is the most popular and affordable type of scuba rubber, it is not sustainable. A recent development is limestone-based polychloroprene, which is more environmentally friendly than butadiene-based scuba rubber. It can be used to make scuba gear as well as other types of apparel.