In March 1944, McLachlan took charge of Southern Area Command, Melbourne, with responsibility for maritime patrol, convoy escort and anti-submarine warfare in southern Australian waters; he handed over to Group Captain Charles Eaton the following January. Mentioned in despatches on 9 March 1945 for his "gallant and distinguished service", McLachlan returned to action in the South-West Pacific as commander of No. 81 Wing, which comprised Nos. 76, 77 and 82 Squadrons, operating Kittyhawks. As part of the Australian First Tactical Air Force in the Dutch East Indies, the wing was slated to take part in Operation Oboe One, the Battle of Tarakan, in May but was unable to relocate from Noemfoor to its new base on Morotai in time. It fought in Operation Oboe Six, the invasion of Labuan, from June and was based on the island when the Pacific War ended in August 1945.