William Shatner

Admiral James T. Kirk

DeForest Kelley

Dr. Leonard 'Bones' McCoy

James Doohan

Captain Montgomery 'Scotty' Scott

George Takei

Cmdr. Hikaru Sulu

Walter Koenig

Cmdr. Pavel Chekov

Nichelle Nichols

Cmdr. Uhura

Christopher Lloyd

Cmdr. Kruge

Robin Curtis

Lt. Saavik

Mark Lenard

Ambassador Sarek

Merritt Butrick

Dr. David Marcus

Judith Anderson

Vulcan High Priestess

James B. Sikking

Captain Styles

Phillip R. Allen

Capt. Esteban

Robert Hooks

Admiral Morrow

John Larroquette

Maltz

Carl Steven

Spock...Age 9

Vadia Potenza

Spock...Age 13

Stephen Manley

Spock...Age 17

Joe W. Davis

Spock at age 25

Leonard Nimoy

Captain Spock / Elevator Voice

Miguel Ferrer

First Officer

Branscombe Richmond

Klingon Gunner #2

Frank Welker

Spock's Screams

Scott McGinnis

Starfleet Cadet "Mr. Adventure"

Phil Morris

Trainee Foster

Jeanne Mori

Helm Officer

Grace Lee Whitney

Commander Janice Rand (Woman in Cafeteria)

Nanci Rogers

Bar Waitress (uncredited)

Paul Sorensen

Captain

Danny Rogers

Merchantman First Officer (uncredited)