During the interwar years, the 12th Battalion was re-raised as a part-time military unit and during the Second World War undertook garrison duties in Australia, but did not see combat.

Today its lineage is perpetuated by the 12th/40th Battalion, Royal Tasmania Regiment, a unit which continues to serve in the Australian Army Reserve.

The battalion was raised as part of the all volunteer Australian Imperial Force (AIF) within three weeks of the declaration of war in August 1914, and left Australia just two months later.

A period of training in the desert followed to prepare the Australian forces for their eventual transfer to Europe, but in late April they were committed to the Gallipoli Campaign.

The offensive failed, but the campaign continued and the battalion remained served on the Gallipoli Peninsula until early December when it was withdrawn to Lemnos Island for rest.

[2][3] In late December, the Allied forces were evacuated from Gallipoli and the battalion returned to Egypt in January 1916, where the AIF was reorganised and expanded.

[4] In March 1916, the AIF's infantry divisions were transferred to the Western Front, and after arriving in France, the 12th Battalion deployed to the Somme.

[1] During the Second World War, the two battalions remained linked, serving as part of York Force and undertaking garrison duties in the Northern Territory.