Birth of Underwater Demolition Teams (UDT Frogmen)

In 1944, following catastrophic loss of life on shallow coral reefs during the Battle of Tarawa, the United States Navy organized the Underwater Demolition Teams (UDT), the legendary "Naked Warriors" and direct forebears of toda’ Navy SEALs. Establishing their primary Pacific training grounds along the surf lines of Coronado, these elite combat swimmers pioneered naval special warfare.

Equipped with only swim trunks, dive masks, fins, and waterproof satchels of plastic explosives, UDT frogmen swam into heavily fortified enemy beaches ahead of major amphibious assault waves. Under heavy enemy fire, they surveyed water depths, mapped coral heads, and manually detonated underwater steel obstacles and concrete tetrahedrons, blowing open clear navigation channels for incoming troop landing craft.

Their courageous operations at Saipan, Guam, Peleliu, Iwo Jima, and Okinawa saved thousands of American lives and cemented their reputation as some of the bravest combat swimmers in military history. The training traditions developed on Coronado beaches in 1944 remain the foundational bedrock of modern Navy SEAL warfare.