Sea-Air-Land (SEAL) Teams trace their history back to WWII selected from the Naval Construction Battalions in the Spring of 1943. Their mission was to clear obstacles from beaches chosen for amphibious landings. Thus, the Naval Combat Demolition Units (NCDUs) began.

In the Pacific, the NCDUs were consolidated into Underwater Demolition Teams (UDTs).

In 1962 President J. F. Kennedy formed the first seal teams from the UDT's as a maritime counterpart to the U.S. Army Special Forces. The first two SEAL Teams were commissioned to conduct unconventional warfare, counter- guerrilla warfare, and clandestine operations in maritime and riverine environments.