In February 1916 when Cyril Cottam presented himself for enlistment in the First AIF, he stated that he was a 19 year old single labourer from Windsor Street, Launceston. Despite having no formal trade qualifications he was allotted to the 8th Field Company Engineers embarking for overseas at the end of March 1916. He was taken on strength in the field on 21 October 1916. He had a clean record until April 1918 when he was taken into custody and charged with fraudulent conversion of property whilst in London on leave in September 1917. awaiting trial. Two months later with the remainder of his unexpired sentence remitted he re-joined his unit in France.
He was sent back to England to face a court martial and pleaded guilty and was found guilty. He was then sentenced to 120 days hard labour, of which 48 days were remitted for time spent
Post War Cyril Cottam continued working as a labourer. He later married and together he and Mary had five children.