2 CER's lineage is formally traced to 4th Field Company (4 Fd Coy) Royal Australian Engineers, which was raised in the early stages of World War I. Renamed 7th Field Company (7 Fd Coy) in 1915, the unit was renowned for its service in France and Belgium at the Battle of the Somme, Menin Road and on the Hindenburg Line. During World War II, 7 Fd Coy fought the Japanese at Kokoda and on Bougainville.