Today's SEAL (Sea, Air, Land) teams trace their history to the first group of volunteers selected from the Naval Construction Battalions (SeaBees) in the spring of 1943. These volunteers were organized into special teams called Navy Combat Demolition Units (NCDUs). The units were tasked with reconnoitering and clearing beach obstacles for troops going ashore during amphibious landings, and evolved into Combat Swimmer Reconnaissance Units.

The NCDUs distinguished themselves during World War II in both the Atlantic and Pacific theaters. In 1947, the Navy organized its first underwater offensive strike units. During the Korean Conflict, these Underwater Demolition Teams (UDTs) took part in the landing at Inchon as well as other missions including demolition raids on bridges and tunnels accessible from the water. They also conducted limited minesweeping operations in harbors and rivers.

During the 1960s, each branch of the armed forces formed its own counterinsurgency force. The Navy utilized UDT personnel to form separate units called SEAL teams. January 1962 marked the commissioning of SEAL Team ONE in the Pacific Fleet and SEAL Team TWO in the Atlantic Fleet. These teams were developed to conduct unconventional warfare, counter-guerilla warfare and clandestine operations in both blue and brown water environments.

Concurrently, Naval Operations Support Groups were formed to aid UDTs, SEALs, and two other unique units — Boat Support and Beach Jumpers — in administration, planning, research, and development. During the Vietnam War, UDTs performed reconnaissance missions and SEALs carried out numerous offensive operations. In 1967, the Naval Operations Support Groups were renamed Naval Special Warfare Groups (NSWGs) as involvement increased in limited conflicts and special operations.

In 1983, existing UDTs were redesignated as SEAL teams and/or SEAL Delivery Vehicle Teams and the requirement for hydrographic reconnaissance and underwater demolition became SEAL missions.

The Naval Special Warfare Command was commissioned April 16, 1987, at the Naval Amphibious Base, Coronado, Calif. Its mission is to prepare Naval Special Warfare forces to carry out their assigned missions and to develop special operations strategy, doctrine, and tactics.

SEALs (Sea, Air, Land) teams go through what is considered by some to be the toughest military training in the world. Basic Underwater Demolition/ SEAL (BUD/S) training is conducted at the Naval Special Warfare Center in Coronado. Students encounter obstacles that develop and test their stamina, leadership and ability to work as a team.