William Shatner (42)

James T. Kirk (voice)

Leonard Nimoy (42)

Spock (voice)

DeForest Kelley (53)

Leonard McCoy (voice)

George Takei (36)

Hikaru Sulu (voice)

Nichelle Nichols (40)

Uhura (voice)

James Doohan (53)

Montgomery Scott (voice)

Majel Barrett (41)

Christine Chapel / Starfleet Computer (voice)

Stanley Adams (58)

Cyrano Jones (voice) (uncredited)

Roger C. Carmel (40)

Harcourt Fenton Mudd (voice) (uncredited)

Ted Knight (49)

Vendorian / Carter Winston (voice) (uncredited)

Ed Bishop (41)

Asmodeus (voice) (uncredited)

Mark Lenard (48)

Sarek (voice) (uncredited)

David Gerrold (29)

EM / 3 / Green (voice) (uncredited) / Security Ensign (voice) (uncredited)

Billy Simpson

Young Spock (voice) (uncredited)

Lou Scheimer (44)

Romulan Crewman (voice) (uncredited) / Demos / Dramian Guard (voice) (uncredited) / Lemus / Aquan Harvester (voice) (uncredited)

Keith Sutherland

Young Sepek (voice) (uncredited)

Norm Prescott (46)

Orion lieutenant / Orion ensign (voice) (uncredited) / Romulan Commander (voice) (uncredited)

Jane Webb

Lara / Vedala Female (voice) (uncredited)