22-year old Parry, who is currently with the Wales squad preparing for the forthcoming Six Nations campaign, will join the Ospreys in the summer from Newport Gwent Dragons.
Hailing from Haverfordwest, for whom he played his first rugby, Parry made a positive impression in the Principality Premiership with Llandovery, earning himself a development contract at the Dragons. Capped at age-grade level by Wales, he has made 48 appearances to date for the Rodney Parade based region.
His form and potential was first recognised by the national set-up when he was called into the training squad ahead of last summer's tour to Japan, and although he didn't make the trip, he has this week been added to the national squad ahead of next weekend's game against Italy. Parry is 1.86m tall and weighs 113kg.
Speaking about his move to the Ospreys, Parry said:
"I'm very excited to be joining the Ospreys from next season. They're a quality team who challenge at the top four of the RaboDirect every year so I'm really looking forward to this opportunity and the challenges that come with being an Ospreys player.
"I feel this is the right place for me to continue improving and develop as a young rugby player, working day in, day out with top quality coaches and players. My long term ambitions as a player are to be involved in an Ospreys team that will continue to challenge for success and silverware year on year and, also, to hopefully make the step up to the next level and become a Welsh international."
Rugby Operations Manager at the Ospreys, Andy Lloyd, said that the coaching team at the region were delighted to have secured Parry's services for the next four years.
"Sam is a player that was identified by the coaching team some time ago as a player with the right attributes to be an Osprey, so when we were made aware that he was coming off contract and there was a possibility of adding him to our squad for 2014/15 and beyond we didn't need to think twice.
"He's a young man still learning the game but there are a lot of good things about him and we feel he will strengthen the squad. He's physical and will bring something different to the group. He's athletic, he's good over the ball, and the set-piece is a real strength.
"We see him as someone with a lot of potential, who will thrive at the Ospreys. He's just been called up by Wales ahead of the Six Nations, which shows how highly regarded he is as a player. We've looked in detail at his game and his personality, and we feel that he is a good character and a good player who will fit well into our environment. He's a hard worker with a lot of ambition who wants to play a lot of games for the Ospreys and for Wales in the future and hopefully we will help him to achieve those aims."