Remembering the Battle of Okinawa On April 1, 1945, American forces launched an amphibious assault on Okinawa. The battle that followed was one of the most intense and costly in the Pacific Theater during World War II. For over 80 days, U.S. soldiers, sailors, airmen, and Marines fought a fierce Japanese resistance through torrential rains, unforgiving terrain and relentless enemy attacks. American forces persevered, securing the island by late June. Over 12,000 service members gave their lives