The World War II Attack on Sydney Harbour
occurred in late May and early June 1942, when submarines
belonging to the Imperial Japanese Navy
made a series of attacks on the cities of Sydney
in New South Wales
, Australia. On the night of 31 May – 1 June, three Ko-hyoteki class midget submarines
, each with a two-member crew, entered Sydney Harbour, avoided the partially constructed Sydney Harbour anti-submarine boom net
, and attempted to sink Allied
warships. After being detected and attacked, the crews of two of the midget submarines scuttled their boats and committed suicide without engaging Allied vessels. The third attempted to torpedo the heavy cruiser USS Chicago
but instead sank the converted ferry HMAS Kuttabul
, killing 21 sailors.
Immediately following the raid the five Japanese fleet submarines that carried the midget submarines to Australia embarked on a campaign to disrupt merchant shipping in eastern Australian waters. Over the next month the submarines attacked at least seven merchant vessels, sinking three. As part of this campaign, during the early morning of 8 June two of the submarines bombarded the ports of Sydney and Newcastle.