Japanese Missions Against Sydney Harbor

May 29, 1942
I-21 launches its E14Y Glen seaplane to reconnoiter Sydney Harbor. At 0420, it circles twice over the harbor near where the heavy cruiser USS Chicago CA-29 is anchored. First thought to be an American plane, RAAF fighters are sent to intercept, but are unsuccessful. It returns and reports sighting a 'battleship'. Captain Sasaki orders his forces to prepair for an attack on Sydney Harbor

May 30, 1942
I-24 arrives off Sydney, moving in position to launch its midget submarine.

May 31, 1942
Three Type A midget submarines were launched by a Type C1 'mother submarine'. These enter Sydney Harbor.

Midget Submarine M27 became entangled in the boom net across the harbor (between Chowder Bay to Watsons Bay) and her occupants blew her up.

Midget Submarine M24 launced by I-24 entered the harbor and fired torpedoes at the USS Chicago. They missed, but one hit the barracks ship HMAS Kuttabul, killing 21. This midget submarine were not found, until located in 2006.

Midget Submarine M22 launched by I-22 was destroyed by depth-charges before it had fired any torpedoes. The remains of two of the midget submarines are displayed at Australian War Memorial and Australian War Memorial Annex.

June 8-9, 1942
During the night of June 8-9, 1942 Japanese submarine I-24 shelled Sydney and Newcastle.