Thomas attended King Edward VII School in Houghton, Johannesburg, South Africa with the likes of Joe van Niekerk and Bryan Habana. Despite being born and raised in South Africa, Thomas began his professional rugby career in the town of his father's birth, Newport, Wales, playing for the Newport RFC youth team.[1] Thomas came through the ranks at Newport, eventually making his debut for the Black-and-Ambers in 2003. He made six appearances for Newport in the 2002-03 season, and was rewarded with a development contract with the Newport Gwent Dragons regional side. Thomas made a try-scoring debut for the Dragons in October 2003 against the Glasgow Warriors, but divided his 2003-04 season between Newport RFC and the Dragons, making 15 appearances for Newport and 16 for the Dragons.

The 2004-05 season saw Thomas finally establish himself as a regular in the Dragons squad, making 27 appearances and scoring two tries, as the team finished in 4th place in the Celtic League. Thomas made a further 30 appearances in 2005-06, but he was unable to prevent the team from slipping to 8th place in the Celtic League, forcing them to have to play a play-off match against Rugby Parma to determine qualification for the 2006-07 Heineken Cup.

Thomas was involved in the play-off, but could not prevent the 24–15 loss that condemned the Dragons to playing in the European Challenge Cup in 2006-07. The team went all the way to the semi-finals of the Challenge Cup, before losing 46-29 to eventual champions ASM Clermont Auvergne. Thomas had missed most of the season due to a back injury, but was available for the Challenge Cup semi-final and the final three games of the Celtic League. Since then, Thomas has been ever-present for the Dragons in the 2007-08 season, and has so far scored three tries — a personal record for one season — including two in one match against Newcastle Falcons on 3 October 2007, the first time he has scored more than one try in a game for the Dragons.

Thomas's international career has so far been largely uneventful. He has made appearances at three different levels for Wales, beginning at Under-19 level while still playing for Newport Youth. Following his displays for Newport RFC, Thomas was rewarded with a spell in the national U-21 side, but it was not long before he had reached the age limit for that team.

In 2006, Thomas finally made his debut for the Wales senior team, coming on as a replacement for Adam Jones in the 57th minute of a match against Argentina on 17 June 2006. 14 months then passed before Thomas made another appearance for the national team, again as a substitute, but this time in a 62-5 defeat by England.

Clubs:
2003-2004 Newport RFC
2003- Newport Gwent Dragons