 In April 1918, it took part in defending against the German Spring Offensive, before the Allies launched their own last-ditch effort as part of the Hundred Days Offensive.The battalion was disbanded in October 1918 due to manpower shortages in the AIF and most of its men were sent to reinforce the other three battalions of the 5th Brigade.In 1921, the 19th Battalion was reformed as part of the Citizens Forces (later the "Militia"), becoming known as the 19th Battalion (The South Sydney Regiment).