Until 1933, the Combined Fleet was not a permanent organization, but a temporary force formed for the duration of a conflict or major naval maneuvers from various units normally under separate commands in peacetime.

The Western Fleet was a reserve force consisting primarily of obsolete ships deemed unsuitable for front-line combat operations, but still suitable for commerce protection and coastal defense.

After the devastating carrier losses at Midway and in the Solomon Islands campaign, the navy re-organized into a number of "Area Fleets" for local operational control of various geographic zones.

As the war situation deteriorated for the Japanese and the territories controlled by the "Area Fleets" fell one after another to the United States Navy, the Imperial General Headquarters and the Imperial Japanese Navy General Staff acted to force the American fleet into a "decisive battle" in the Philippines per the Kantai Kessen philosophy.

By the time of the final suicide mission of the battleship Yamato in Operation Ten-Go, the Combined Fleet had ceased to exist as an effective combat force.