A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes combat. Such personnel are also known by the more formal names of combat diver, combatant diver, or combat swimmer. The word frogman arose from Italian "uomo rana" around 1940 from the appearance of a diver in a shiny drysuit and large fins.

Combat swimming is often used to mean combat diving. Such actions are a historical form of "frogman" activity and an important feature of naval special operations.

The term frogman is occasionally used to refer to a civilian scuba diver. Some sport diving clubs include the word Frogmen in their names. The preferred term by scuba users is diver, but the frogman epithet persists in informal usage by non-divers, especially in the media and often referring to professional scuba divers, such as in a police diving role.