thumb|Surface supplied commercial diving equipment on display at a trade show
Commercial diving may be considered an application of professional diving where the diver engages in underwater work for industrial, construction, engineering, maintenance or other commercial purposes which are similar to work done out of the water, and where the diving is usually secondary to the work.
In some legislation, commercial diving is defined as any diving done by an employee as part of their job, and for legal purposes this may include scientific, public safety, media, and military diving.