[13] Sailing via Albany, in Western Australia, and making stops at Durban, Cape Town and Dakar, the battalion arrived in the United Kingdom on 9 July 1916.

[15] After arriving in Le Havre, in France, the battalion moved by rail to Bailleul, from where they marched to the front, occupying a section of the line around Armentières.

[16] Assigned to a "nursery" sector, for the next month they rotated between occupying the forward trenches and undertaking training courses, as the battalion was introduced to life on the European battlefield.

Although the battalion gained some experience of combat over Christmas, when they launched raids against the German lines,[17] their first major battle did not come until mid-1917, by which time the focus of British operations had shifted to the Ypres sector in Belgium.

[20] Despite suffering around 200 casualties from Allied gas-shells that had dropped short, the battalion went "over the top" at the appointed hour and, after skirting the large crater the mine had caused, secured their objective.

Heavily depleted, with a frontage of just 242 men, they fought around Augustus Wood, where the Germans had established many pillboxes before heavy rain washed away any hope of an Allied breakthrough.

There, the 33rd took part in heavy fighting when the Australians counter-attacked at Hangard Wood on 30 March, before finally turning back the German attack on Villers-Bretonneux on 4 April.

[32] Following up the Americans, the 33rd held off a strong counter-attack by German forces around Gillemont Farm, before carrying out mopping-up operations towards Bony.

After this, in early October, the battalion was pulled back to the Abbeville area, taking up billets in Citerne, where they remained until the armistice was signed in November.

They remained linked until October 1936,[36] when the 33rd Battalion was reformed in its own right as part of an expansion of Australia's military force as tensions rose in Europe, raising concerns of a future war.

[41] During World War II, due to the provisions of the Defence Act, which precluded Militia units from being sent outside Australian territory to fight,[42] the battalion remained in Australia undertaking garrison duties.