Landing in Cairns, Queensland, the battalion was sent to Ravenshoe for leave before reforming around Townsville in April. While there, the 55th/53rd were transferred first to the 12th and then the 3rd Brigade, with whom it undertook garrison duty around Townsville. It was later transferred to the 11th Brigade and, despite being a Militia battalion, it eventually achieved AIF status, which meant that it could be deployed to fight in any theatre of war. In December 1944, the battalion was sent to Boungainville where it took part in the fighting throughout 1945 as part of the 11th Brigade. During this time it undertook patrol operations in the Central and Northern Sectors of the island and although it experienced several contacts with the Japanese, it fought no major battles against them before it was withdrawn to the main Australian base around Torokina in May, where it remained until the war came to an end. It was during the period of demobilisation that Francis Donovan served as the battalion's adjutant.