[5] On 23 March 2010, Thomas competed in the I-1 World Muaythai Grand Prix 2010, a 66 kg/145 lb one-night, eight-man tournament held in Kowloon Bay, Hong Kong and was eliminated at the quarter-final stage when he lost a split decision to Santichai Or.
On 6 July 2011 he defeated Maes Chantha by technical knockout at the Olympic Stadium in Phnom Penh, Cambodia to regain the ISKA World Welterweight Kun Khmer title.
[11][12] On 20 January 2012, he lost on points against Ludovic Millet in a five-rounder for the vacant ISKA World Super Welterweight (-69.5 kg/153.2 lb) Oriental Championship in Meaux, France.
[13] In 2012, he signed with the Glory promotion and was included in the 2012 Middleweight Slam tournament, replacing Tie Yinghua on short notice to join sixteen of the world's best fighters at 70 kg/154 lb.
[24][25] He TKO'd Marcel Tratnik in round two at Day of Destruction 7 in Hamburg, Germany on 14 September 2013 to win the WFCA European Junior Middleweight (-69.85 kg/154 lb) K-1 Championship.
[26] Thomas competed at the -65 kg/143 lb Thai Max tournament in Meyreuil, France on 19 October 2013, defeating Alessio D'Angelo by unanimous decision in the quarter-finals before losing to the eventual champion Damien Alamos by the same margin in the semis.