The 34-year-old, the only Welsh player to have won a URC (Ospreys 2012) and English Premiership (Harlequins 2021) title, won 37 caps for his country and was first-choice throughout the 2015 World Cup.
He made his Wales debut in Japan in 2013 and went on to win 34 caps up to 2017. He then earned a recall by Warren Gatland during the 2023 Guinness Six Nations, when he added three more appearances to his cap tally.
After 10 seasons at the Ospreys, he moved to London to join Harlequins, helping them to become English champions, before switching to Worcester Warriors. He returned to the Ospreys on compassionate ground in February 2022.
Baldwin will link-up with former Harlequins forwards coach Alex Codling at Newcastle. He has previously had some coaching experience at Bridgend Ravens.
“It is a tough decision knowing I can still play professionally, but someone once told me it’s better to retire a year early than a year too late,” Baldwin wrote on social media.
“Thank you to everyone that’s made it the journey it’s been. I’ve loved every minute and will be eternally grateful to the game and the people involved.”
Baldwin is the second international forward at the Ospreys to retire this summer, following in the footsteps of lock Bradley Davies. He has also gone into coaching at the Ospreys Academy and Bridgend.
Codling has taken over as head coach at the Falcons for next season and is delighted to have recruited Baldwin into his back room team.
“I first met Scott when I was forwards coach at Harlequins, I enjoyed working him and you could see straight away he was a top professional,” said Codling.
“He’s got a huge amount of experience from playing in the Premiership, URC (United Rugby Championship) and internationally over a number of years, and he’ll bring a wealth of knowledge to the role.”