Conbeer, 25, has been without a club since being released by Scarlets at the end of last season.
A clinical finisher, Conbeer was a key feature for the west-Wallians before joining the Ospreys, making over 80 appearances during his time with the region and finding the try line on over 30 occasions.
Conbeer has represented Wales at sevens and was Wales Under-20’s record appearance holder with 23 before he was overtaken by Morgan Morse earlier this season, who now holds the record with 24.
Speaking on joining the Ospreys, Conbeer said:
“It’s been really easy to get settled in with the Ospreys. I know a fair few of the boys already but everyone at the club has made me feel welcome since I’ve been here.
“I’m looking forward to stepping onto the pitch with the team and making an impact wherever I can.”
Head Coach, Toby Booth, said:
“With Keelan [Giles] currently out injured, it made a lot of sense for us to bring in someone of Ryan’s calibre at the wing position. He’s got a proven track record and is someone we still see as having a bright future in rugby.”
[Lead image: Ospreys Rugby]