 He joined the Glamorganshire Constabulary in November 1904, and was posted to Mountain Ash, remaining there until the start of the First World War.Thomas first played rugby for local Rhondda clubs, Ferndale and Penygraig before moving to Mountain Ash, the team he would captain during the 1904/05 season.He faced his first international opposition when he was chosen to represent Glamorgan, an invitational county team that faced the touring South Africans in 1906.