The Australian merchant ship NANKIN was sunk by the German raider, THOR, in the Indian Ocean. The captain of NANKIN at the time was CAPT B. W. Dunn, RANR, who had entered the RAN College in 1919 as a Cadet Midshipman. He was withdrawn from the College in 1920 as numbers were reduced due to economic reasons. Dunn, and his crew were made Prisoners of War, and placed in a Japanese POW Camp. CAPT Dunn survived his incarceration, and was released from the camp in 1945.
The Japanese raiders, AIKOKU MARU and HOKOKU MARU, captured the British merchant ship GENOTA off Madagascar. Later in the month a seaplane from one of the raiders conducted a reconnaissance of the British base at Diego Suarez, in preparation for a midget submarine attack on the port. This attack was conducted on the same day, (in fact, taking into account time zone changes the attacks were only 70 minutes apart), as the midget submarine attack on Sydney Harbour on 30 May/1 June.