Biyombo joins forward DeMarre Carroll as the second free agent to agree to a deal with the Raptors this week. Together, Biyombo and Carroll – who agreed to a four-year, $64 million deal – are expected to play a part in reshaping the Raptors' defense next season.
Toronto general manager Masai Ujiri and coach Dwane Casey want a tougher, more physical roster.
Biyombo became an unrestricted free agent when the Charlotte Hornets declined to extend him a qualifying offer after the season.
Biyombo, 22, averaged 4.8 points, 6.4 rebounds and 1.5 blocks in 64 games for the Hornets last season. An athletic 6-foot-9 frontcourt player, Biyombo was the seventh overall pick of the 2011 NBA draft.