Following training, the battalion was deployed to New Guinea, arriving in Milne Bay in early August 1943. It saw action in the final stages of the Salamaua–Lae campaign in September 1943. The 2/15 took part in the landing at Lae, the first amphibious operation undertaken by Australian forces since the failed Gallipoli campaign in 1915. During the operation, the 2/15th was initially assigned the task of securing the beachhead following the 20th Brigade's landing. After being relieved it joined the advance west towards the town, slowed by heavy rains that turned the many creeks in the area into raging torrents, which were invariably covered by heavy Japanese fire from the opposite bank.