The attack on Pearl Harbor was a surprise attack against the Unite States' naval base at Pearl Harbor, Hawaii by the Japanese navy, on the morning of Sunday, December 7, 1941, resulting in the United States becoming involved in World War II. It was intended as a preventive action to remove the U.S. Pacific Fleet as a factor in the war Japan was about to wage against Britain, the Netherlands, and the United States. Two aerial attack waves, totaling 353 aircraft, launched from six Japanese aircraft carriers.