Thomas began his football career at Queens Park Rangers, but was released at the end of his two-year scholarship. He moved into non-league football alongside studying for a BTEC National Certificate in Media. He was top scorer for Waltham Forest in the 2005–06 Southern League Eastern Division, top scorer for Thurrock in the Conference South the following season, and repeated the feat with Fisher Athletic, also in the Conference South, in 2007–08, before making his debut in the Football League with Dagenham & Redbridge in October 2008.
He joined Conference Premier club Grays Athletic on loan in December 2008; he made eight appearances and scored twice before his loan ended at the end of January 2009. He joined Rushden & Diamonds in March 2010 on loan until the end of the season, but never appeared for the first team, and was transfer-listed by Dagenham & Redbridge as they restructured the team following their promotion to League One.