No. 12 Squadron began to move to Darwin in July 1939, with its advance party arriving there on the 24th of the month. The squadron was the first RAAF unit to be permanently based in the Northern Territory and was initially stationed at Darwin’s civil aerodrome. Seven No. 12 Squadron Ansons were based in Darwin by late August, and these began flying reconnaissance patrols on the last day of the month.

The Demons were replaced with CAC Wirraway general purpose aircraft at Laverton on 1 September, and all of the squadron’s aircraft had arrived in Darwin by 17 September. The squadron’s flying was reduced during September and October to make personnel available to improve the aerodrome’s facilities, but by the end of October it had returned to normal operations. These included escorting shipping, maritime reconnaissance and coastal patrols.