After impressing for Newport in the Principality Premiership and British and Irish Cup, Coombs was given a chance by Dragons boss Paul Turner and made his Dragons debut at Connacht before coming off the bench at home against the Ospreys and making his first Regional start last Sunday against Glasgow Warriors.
Premiership coaches, rugby journalists and WRU and Regional performance development staff select the monthly Principality Premiership winners who receive £100 in prize money from the Principality Building Society, title sponsors of the competition.
Coombs, who began playing rugby at Nelson RFC and moved onto Newport as a youth player, said: "It's great to get this kind of recognition, both in terms of this award and obviously in terms of playing for the Dragons, I have already learnt a lot from gaining some game time with them, and now I want to take that back to Newport.
"We have a massive game against Neath on Saturday, and although Neath are more or less certain for the title, there is still a battle on for the top four places in the league. Both ourselves and Neath have been good defensively this season so I think it will come down to which side takes its chances on the day.
"As a club we have had a stop-start season . After finishing second last year, it would have been great to win the Principality Premiership this season but a few results have let us down, in particular with recent losses to Cardiff and Llanelli.
"Our main aim now is to finish in the top four to gain automatic British and Irish Cup qualification, and once we get into the Premiership play-offs, it would be great to win them and gain some silverware from the season."
Coombs says his side have been buoyed this season by the introduction of the British and Irish Cup.
"We thoroughly enjoyed the experience of playing in the British and Irish Cup and we're desperate for more of the same. We produced a few shock results and enjoyed the high standard of competition and the physicality that came with it," he said.
Newport head coach Sven Cronk added: "Andrew has been a great captain both this season and last, truly leading by example. He does the dogged work when required but is also a great ball carrier. He deserves this award and the recent recognition by the Dragons set-up.
"Although we are disappointed with some of our games this season, losing too many matches by three points or less, we still have something to play for as we aim to finish in the top four and with the new play-off championship to look forward to. There will be no lack of motivation on Saturday for our game against league leaders Neath."
Andrew Coombs fact file:
Born: 27.10.84, Merthyr Tydfil
Position: No 8
Player most admired: Xavier Rush, for his go-forward game
Sportsman most admired: David Beckham
Biggest impact on career: Father Jon, who has been a huge influence, and coaches at Pontypool and Newport
Occupation outside rugby: Salesperson for a software company
Other sports: Football, snooker