Jim Carrey as Ivo Robotnik / Gerald Robotnik

Ben Schwartz as Sonic (voice)

Keanu Reeves as Shadow (voice)

Idris Elba as Knuckles (voice)

Colleen O'Shaughnessey as Tails (voice)

James Marsden as Tom

Tika Sumpter as Maddie

Lee Majdoub as Agent Stone

Krysten Ritter as Director Rockwell

Adam Pally as Wade

Natasha Rothwell as Rachel

Shemar Moore as Randall

Alyla Browne as Maria

Tom Butler as Commander Walters

Jorma Taccone as Kyle Lancebottom

Sofia Pernas as Gabriella

Cristo Fernández as Pablo / Juan

James Wolk as Young Walters

Brett Tutor as Prison Guard

Richard Sutton as G.U.N. HQ Security Guard

Will Austin as G.U.N. Heli Pilot

Bola Okun as Military Man

Reggie Banigo as Rockwell's Assistant

Barry Calvert as 70s G.U.N. Soldier

Brendan Murphy as Robotnik Proxy

Toru Nakahara as Japanese News Reporter (voice)