Thomas Bonner was a trialist who played against Bristol City X1 behind closed doors on the 17th July 2004
Exeter won 1-0 and Thomas scored. He was a Republic of Ireland Youth International who had been released by Wolves.

He started his professional career at Wolverhampton Wanderers in the summer of 2002. After his trial at Exeter he returned to Ireland and signed for Finn Harps. He left them after playing 6 games and later played for Derry side Institute FC. 

Thomas signed for Finn Harps again  from Institute in 2010 season and scored seven goals in 29 appearances that year, adding 25 more appearances the following year. In 2012 Thomas made another 18 league appearances. Thomas before leaving the club in August 2014.