Deiniol Jones is originally from Cardigan where he attended Ysgol Gyfun Llandysul. He went on to study Chemistry at Bath University in 1997 where he caught the eye of the scouts of Bath RFC. After spending three years playing for Bath, in 2000 Deiniol signed for Ebbw Vale on loan before joining Bridgend, The Celtic Warriors and the Cardiff Blues in 2004. Deiniol gained international honours representing Wales at Under 18, 19 and 21 age grades before making his debut for the senior Wales team against Samoa in November 2000, and also won caps on the tour to Japan in 2003. One of the Blues' most consistent players he was near ever present in the Blues team during the 2006/07 season playing in 30 of the 32 matches that season.