Ibe made nine starts last season for the Owls, making 42 tackles. He appeared in 33 career games for Rice.
He joins a South Carolina team that went 9-4 last year in coach Will Muschamp's second season. The Gamecocks, who lose both starting safeties, finished second in the SEC East at 5-3, two games behind Georgia.
"I talked to Coach Muschamp and I talked to (defensive coordinator) Travaris Robinson," Ibe told The State newspaper in Columbia, S.C. "(Muschamp) said I'm a player with experience and I can, if I'm better than the guys, come in and play right away. He feels like they are trying to win an SEC championship and they need to do that right away."
Ibe was the third Rice grad transfer to announce a new destination over the weekend.
Coveted offensive tackle Calvin Anderson is heading across state to play for Texas after also visiting Alabama, Auburn, Oklahoma and Michigan. Defensive tackle Preston Gordon, a three-year starter, will play next season at Texas Tech.