Diving equipment, or underwater diving equipment, is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found to be suitable for diving use.

The fundamental item of diving equipment used by divers other than freedivers, is underwater breathing apparatus, such as scuba equipment, and surface-supplied diving equipment, but there are other important items of equipment that make diving safer, more convenient or more efficient. Diving equipment used by recreational scuba divers, also known as scuba gear, is mostly personal equipment carried by the diver, but professional divers, particularly when operating in the surface supplied or saturation mode, use a large amount of support equipment not carried by the diver.

Equipment which is used for underwater work or other activities which is not directly related to the activity of diving, or which has not been designed or modified specifically for underwater use by divers is not considered to be diving equipment.

The diving mode is largely defined by the type of breathing apparatus used.

This is the diving equipment worn by or carried by the diver for personal protection or comfort, or to facilitate the diving aspect of the activity, and may include a selection from:

The underwater environment usually requires a diver to wear thermal, sting and abrasion protection.

This equipment includes buoyancy control equipment and mobility equipment: Buoyancy control is achieved by ballasting with diving weights and compensating for buoyancy changes during the dive using a buoyancy compensator:

Mobility equipment allows the diver to move through the water and maneuver on the spot: