Born in Porthcawl, a seaside resort near Bridgend, Prydie primarily played football in his early childhood. However, Prydie represented his primary school, Nottage at under 11s rugby, within the Bridgend and District Schools' RU. He played for West Wales A (Under 11s) in their victory over East Wales at Virginia Park, Caerphilly RFC, on 10 April 2003. Prydie made his first ever appearance at the Millennium Stadium on 3 May 2003, when he represented Bridgend Schools' Under 11s v. Cardiff Schools' Under 11s, in the final of the DCThomas Cup.
His rise to prominence began in summer 2009, when he was noticed by Scott Johnson, the director of coaching for the Ospreys regional team. Prydie was then fast-tracked through the Ospreys age-grade system, and by the end of the year was in the senior side. He made his Ospreys senior debut on 12 December 2009 as a second-half replacement in their Heineken Cup match against Viadana. This made him the youngest player in Heineken Cup history at age 17 years, 292 days, beating the previous record of Leicester Tigers' Richard Governley by 16 days.
In January 2012 it was announced he along with Leicester's Lee Robinson would be joining London Wasps until the end of the season to cover injured duo Christian Wade and Tom Varndell
In May 2012 Prydie joined Newport Gwent Dragons He was released at the end of the 2016-17 season.
On 18 January 2010 Prydie, aged 17, was a surprise inclusion in the 35-man Wales national squad named for the 2010 Six Nations despite playing just seven minutes for the Welsh region the Ospreys. Despite media speculation that Prydie would be named in the squad, he was still shocked at his selection. He was notified by a text message from Wales national coach Warren Gatland only 20 minutes before the public announcement of the squad; he initially thought that the message was part of an elaborate practical joke by some of his Ospreys teammates. At the time of his selection, Prydie had never met or spoken to Gatland.
Prydie was named on the wing in the starting team for Wales' final 2010 Six Nations match against Italy and became the youngest cap in Wales' rugby history. The previous youngest to play for Wales was Norman Biggs, who was 18 years, 49 days old when he made his debut in 1888 against the New Zealand Natives. Prydie was 18 years, 25 days old at the time of the Italy match on 20 March. Prydie, who by the time of the Italy match had made only two starts and played 167 minutes for the Ospreys senior side, also surpassed Mathew Tait of England as the youngest ever to play in the Six Nations.
In June 2010 Prydie became Wales youngest try scorer at 18 years and 102 days against South Africa, overtaking the record set by Tom Pearson in 1891.
In 2012 Prydie made his debut for the Wales under-20 team in the Junior World Championships, two years after making his debut for the Wales senior team.
In May 2013 he was selected in the Wales national rugby union team 32 man training squad for the summer 2013 tour to Japan.