The best shore-area special operations force has a secretive past. Commissioned in 1962, the Navy SEALs focus mainly on gathering intelligence and precision strike operations. Despite common belief, the origin of the elite group is the Amphibious Scouts and Raiders during the 1940s. When the need for amphibious abilities arose, a Joint Training Force created an Amphibious Boat School to train crew members. The Amphibious Scout and Raider School began its’ extreme training in 1942, with Phil Bucklew being among the volunteers. The troops were trained to recognize landmarks on the shore at night, navigate scout boats, and stealth swimming.
Source: https://nationalinterest.org/blog/buzz/you-cant-beat-them-origins-legendary-navy-seals-94941