In February 1942, along with the majority of the 2nd AIF, the 2/9th was withdrawn to Australia in response to the threat posed by Japan's entry into the war following the attacks on Pearl Harbor and in Malaya. Returning via Bombay and Colombo, the 2/9th arrived in Australia, landing in Port Adelaide, South Australia, in March 1942 and from there proceeded to camp in Sandy Creek, near Gawler. The battalion remained there until April when it was moved to Tenterfield, New South Wales, and then Kilcoy, Queensland, where it carried out training prior to departure overseas. At this time, the strategic situation in the Pacific was finely balanced. In July, the Japanese had landed on the northern New Guinea coast and had begun advancing along the Kokoda Track towards Port Moresby, amidst heavy fighting. On 6 August 1942, the order to deploy came and the battalion embarked from Brisbane along with the rest of the 18th Brigade, bound for Milne Bay in New Guinea where the 2/9th arrived on 21 August to help reinforce the garrison there, due concerns about a possible Japanese landing there to secure the adjacent airfields.