Balabac Strait
"Robalo" departed Fremantle on 22 June 1944 on her third war patrol. She set a course for the South China Sea to conduct her patrol in the vicinity of the Natuna Islands. After transiting Makassar Strait and Balabac Strait (which was well-known to be mined), she was scheduled to arrive on station about 6 July and remain until dark on 2 August 1944. On 2 July, a contact report stated "Robalo" had sighted a "Fusō"-class battleship, with air cover and two destroyers for escort, just east of Borneo. No other messages were ever received from the submarine, and when she did not return from patrol, she was presumed lost.