Initial Japanese Navy Order of Battle, 5 Fleet to 11 Air Fleet and Naval Districts

This was the principal Japanese submarine force, though not all Japanese submarines were assigned to it. The entire force was deployed against Hawaii at the start of the Pacific War, to pick off any survivors of the Pearl Harbor attack that tried to escape to the open sea.

As it turned out, not a single U.S. warship was sunk by this force, which lost one of its submarines to aircraft attack. Both sides would learn that warships were difficult targets and that submarine operations near well-defended bases were poor strategy.