 He made his debut for the Ospreys on 10 January 2004.However he was soon followed by Adam Jones who made his first appearance for Ospreys on 13 March 2004 against Stade Toulousain.In 2005–06, Duncan Jones took over as captain of the Ospreys, following an injury to Barry Williams, and he was appointed captain for the 2006–07 season, during which he led the team to the Celtic League title.