He scored eight league tries in total, including four in April - against Swansea, Bridgend and Bedwas away from home and Aberavon at Church Bank. Roberts follows team mates Rhodri Williams, Shaun Miles, Matthew Jacobs and Kieran Murphy to have been nominated by Premiership coaches, WRU performance staff and journalists to claim the accolade this season.
He said, "The coaching at Llandovery is excellent and we have been a really tight knit group throughout the past two years. The type of rugby we play has suited me down to the ground and there's a great bunch of boys at the club.
"We were disappointed not to beat Llanelli in the Play-Off semi-final, but overall we are pleased with our season and it couldn't have gone better for me personally. After initially joining Glamorgan Wanderers when I started at Glamorgan University, I returned to Llandovery two seasons ago and the move has really given my career a fresh start."
Pat Ashman, Sponsorship and Events Manager at Principality Building Society, said: "Jack has had a great season with Llandovery, in what has been the team's most successful season ever. Jack has played a big part in that and we have seen some really exciting rugby from him in the last month in particular. He is a well-deserved winner of the final Principality Premiership Player of the Month for 2012/2013 and we look forward to seeing him build on this success next season."
Jack Roberts factfile:
Born: 20.11.91, Bangor
Biggest influence on career: Father Mark who drove me to every Welsh Schools Under 16 training session in south Wales and was my coach at Pwlleli as a junior
Most admired player: Brian O'Driscoll
Most admired sportsperson: Paul Scholes
Education: Ysgol Glan Y Mor, Pwllheli, just completed an Accounting and Finance Degree at University of Glamorgan