May 29, 1942
(IJN) I-21 launches its E14Y Glen seaplane to reconnoiter Sydney Harbor. At 0420, it circles twice over the harbor near where heavy cruiser USS Chicago CA-29 was anchored. First thought to be an American plane, RAAF fighters were sent to intercept, but are unsuccessful. The seaplane returns safely and reports sighting a "battleship" in Sydney Harbor. Captain Sasaki orders his forces to prepare for an attack against Sydney Harbor.
May 30, 1942
(IJN) I-24 arrives off Sydney, moving in position to launch its midget submarine.
May 31, 1942
(IJN) Three Type A midget submarines were launched by a Type C1 mother submarines including I-22, I-24 and I-27. These enter Sydney
Midget Submarine M27 launched by I-27 became entangled in the
boom net across Sydney
Harbor between Chowder Bay to Watsons Bay. Entangled, her occupants scuttled the submarine using the explosive charges at 10:35pm killing both crew members and sinking to the bottom of Sydney
Harbor. Afterwards during early June 1942 this midget submarine was salvaged by the Royal Australian Navy (RAN) and the remains of the crew recovered and returned to Japan.
Midget Submarine M24 launched by I-24 entered
the harbor and fired torpedoes at USS Chicago CA-29. They missed, but one hit the barracks ship HMAS Kuttabul, killing 21.
This midget submarine were never located until discovered by SCUBA divers 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
(IJN) During the night of June 8-9, 1942 Japanese submarine I-24 shelled Sydney and Newcastle.