Thomas joined the Academy at Swansea City when he was 9 year old and signed his first professional contract with the club in July 2015. During his time at the Liberty Stadium he helped win three FAW Youth Cup titles and was part of the Premier League 2 double-winning squad in the 2016–17 season. In January 2018, he joined Carmarthen Town on loan to cover for injured goalkeeper Lee Idzi. He played four Welsh Premier League and one Welsh Cup game for the "Old Gold". In June 2018, Thomas signed a two-year contract with Forest Green Rovers, who were about to embark on their first season in the English Football League. He made his debut in professional football on the opening day of the 2019–20 season, keeping a clean sheet in a 1–0 win over Oldham Athletic. He signed a new contract with Forest Green Rovers in November 2019.