Tautau Moga will link up with his fifth NRL club after finalising a one-year deal with South Sydney on Monday.
At just 26, the well-travelled centre has already played for Newcastle, Brisbane, North Queensland and the Sydney Roosters in a 73-game NRL career.
He has represented Samoa in three Test matches and was part of the Cowboys' squad that won the 2015 NRL Premiership.
Rabbitohs head of football, Mark Ellison, said: "Tautau is a great addition to our squad next season as we look to add some experience to our backline depth.
"A couple of injuries have stalled him throughout his career but when he has been fit to play he has proven that he can be one of the most destructive outside backs in the game," Ellison said.
