By early 1916, recruiting in Australia had made it possible to replace the ANZAC losses. The AIF in Egypt was expanded to four divisions with a fifth being raised in Australia. The overseas divisions were organised into I ANZAC Corps (1^st and 2^nd Australian Divisions, and the New Zealand Division) and II ANZAC Corps (4^th and 5^th Australian Divisions).⁵⁸ Beginning in March the troops were moved to France, and by July and August were heavily involved on the Western Front. The 5^th Division was the first to engage the Germans on 5 July 1916 in a small but bloody engagement at Fromelles in northern France. Shortly after, the 1^st, 2^nd and 4^th Divisions became embroiled in the first Somme offensive, at Pozieres and Moquet Farm.⁵⁹ (In the six weeks of operations, the Australian Divisions lost approximately 23,000 officers and men.) In December the 3^rd Australian Division arrived in France, having been training in England since its arrival from Australia in July.⁶⁰

In the following year, 1917, the Australians were again heavily engaged, in March at Bapaume, in May and June at Bullecourt and Messines, and from September to November in the great battles of the Ypres offensive - Menin Road, Polygon Wood, Broodseinde, Poelcapelle and Passchendaele.⁶¹ The casualties sustained made it difficult to keep the Australian divisions up to strength and a partially formed 6^th Australian Division was disbanded in order to provide reinforcements.⁶² In November 1917, the five divisions were formed into the Australian Corps; though it would not be until May 1918 that an Australian - Lieutenant General Sir John Monash, previously GOC 3^rd Australian Division, would command it.⁶³

In March and April 1918, the Australian Corps took a prominent part in preventing the capture of Amiens, Hazebrouck and Villers-Brettoneux, during the German 'Michael' offensive. During the final allied offensives of the war, it was engaged at Mont St Quentin and Albert, and in the penetration of the Hindenburg Line.⁶⁴ The Corps, which had been fighting almost continuously since March, had gone into reserve to rebuild for the next offensive when the Armistice was signed on 11 November, 1918.⁶⁵

The AIF strength in France was maintained at some 117,000 men.⁶⁶ Its battle casualties for the three years of trench warfare between 1916 and 18 were over 181,000; of whom over 46,000 died. Another 114,000 were wounded, 16,000 gassed and nearly 4,000 were taken prisoners of war. In terms of total deaths per 1000 men mobilised, the AIF figure was 145 - the highest of all the British Commonwealth armies.⁶⁷