William Shatner 
 as Admiral James T. Kirk

Leonard Nimoy 
 as Mr. Spock

DeForest Kelley 
 as Dr. Leonard 'Bones' McCoy

James Doohan 
 as Cmdr. Montgomery 'Scotty' Scott

George Takei 
 as Lt. Cmdr. Hikaru Sulu

Walter Koenig 
 as Lt. Pavel Chekov

Nichelle Nichols 
 as Lt. Cmdr. Uhura

Stephen Collins 
 as Captain William Decker

Persis Khambatta 
 as Lt. Ilia / The Probe

Majel Barrett 
 as Dr. Christine Chapel

Grace Lee Whitney 
 as CPO Janice Rand

Mark Lenard 
 as Klingon Captain

Billy Van Zandt 
 as Alien Boy

Roger Aaron Brown 
 as Epsilon Technician

Gary Faga 
 as Airlock Technician

Franklyn Seales 
 as Crew Member

Joel Kramer 
 as Klingon Crewman

David Gautreaux 
 as Cmdr. Branch

John Gowans 
 as Assistant to Rand

Howard Itzkowitz 
 as Cargo Deck Ensign

Jon Rashad Kamal 
 as Lt. Cmdr. Sonak

Marcy Lafferty 
 as Chief DiFalco

Michele Povill 
 as Lieutenant

Jeri McBride 
 as Technician

Terrence O'Connor 
 as Chief Ross

Michael Rougas 
 as Lt. Cleary

Susan O'Sullivan 
 as Woman

Ralph Brannen 
 as Crew Member

Ralph Byers 
 as Crew Member

Paula Crist 
 as Crew Member

Iva Lane 
 as Crew Member

Momo Yashima 
 as Crew Member

Jimmie Booth 
 as Klingon Crewman

Dave Moordigian 
 as Klingon Crewman

Tom Morga 
 as Klingon Crewman

Tony Rocco 
 as Klingon Crewman

Joel Schultz 
 as Klingon Crewman

Craig Thomas 
 as Klingon Crewman

Edna Glover 
 as Vulcan Master

Norman Stuart 
 as Vulcan Master

Paul Weber 
 as Vulcan Master

Joshua Gallegos 
 as Security Officer

Lisa Chess 
 as Yeoman

Leslie C. Howard 
 as Yeoman

Sayra Hummel 
 as Technical Assistant

Junero Jennings 
 as Technical Assistant

Christopher Doohan 
 as Extra (uncredited)