On 9th July 1918, William Clarke convinced his parents to sign the documentation so that he too could volunteer for enlistment. William was 20 years of age and did not need his parent’s permission. On being accepted, William was allotted to the 3rd Tasmanian Reinforcements that left Melbourne on the SS Zealandic on 5 October 1918, arriving in England on 5 December. The same day he was allotted to the 12th Battalion. After 6 months undertaking training he was finally marched out to the Graves detachment for a six week period. During this time he had at least two admissions to hospital with chest complaints. William departed England on 25 September a couple of weeks short of the anniversary of his departure.
William returned to the family farm at Moltema. Just what happened to William is unclear from the public records, aged just 24 years, William Eric Clarke died and was buried at the Deloraine General Cemetery.