3rd Fleet was initially formed on 15 March 1943, under the command of Admiral William F. Halsey, and was responsible for much of the campaigning in the Pacific in World War II. The fleet was put into reserve on 7 October 1945.
It was reactivated 1 February 1973 at Ford Island in Pearl Harbor as part of a Pacific Fleet reorganization. 3rd Fleet took over the duties of 1st Fleet and the Pacific Anti-Submarine Warfare Force.