- Patrick Duffy
- Â Mark Harris / ... 17 episodes, 1977-1978
- Alan Fudge
- Â C.W. Crawford 16 episodes, 1977-1978
- Belinda Montgomery
- Â Dr. Elizabeth Merrill 15 episodes, 1977-1978
- Richard Laurance Williams
- Â Cetacean crew 11 episodes, 1977-1978
- J. VÃctor López
- Â Cetacean crew 11 episodes, 1977-1978
- Jean Marie Hon
- Â Cetacean crew 9 episodes, 1977-1978
- Victor Buono
- Â Mr. Schubert 6 episodes, 1977
- Anson Downes
- Â Cetacean crew 6 episodes, 1977-1978
- Robert Lussier
- Â Brent 4 episodes, 1977
- Michael J. London
- Â Cetacean crew / ... 3 episodes, 1977
- Kenneth Tigar
- Â Dr. Miller Simon 3 episodes, 1977
- Ted Neeley
- Â Jack Muldoon 2 episodes, 1977-1978
- Fred Beir
- Â Captain Bracy 2 episodes, 1977
- Pamela Peters Solow
- Â Jane / ... 2 episodes, 1977
- Brandyn Barbara Artis
- Â Cetacean crew 2 episodes, 1977
- Neville Brand
- Â Stringer 1 episode, 1977
- Dean Santoro
- Â Ernie Smith 1 episode, 1977
- Sharon Farrell
- Â Charlene Baker 1 episode, 1978
- Lisa Eilbacher
- Â Juliet 1 episode, 1977
- Michele Carey
- Â Belle 1 episode, 1977
- Pernell Roberts
- Â Clint Hollister 1 episode, 1977
- Laurette Spang
- Â Amanda Trevanian 1 episode, 1977
- Art Lund
- Â Adm. Dewey Pierce 1 episode, 1977
- Billy Barty
- Â Moxie 1 episode, 1978
- Dick Gautier
- Â Duke 1 episode, 1978
- Rene Auberjonois
- Â Havergal 1 episode, 1977
- Darleen Carr
- Â Dr. Mary Smith 1 episode, 1977
- John Shea
- Â Romeo 1 episode, 1977
- Kareem Abdul-Jabbar
- Â Thark 1 episode, 1977
- Val Avery
- Â Lew 1 episode, 1977
- Tiffany Bolling
- Â Dilly / ... 1 episode, 1977
- Jamie Smith-Jackson
- Â Bettina Washburn 1 episode, 1977
- Michael Strong
- Â Hugh Trevanian 1 episode, 1977
- Ted Cassidy
- Â Canja 1 episode, 1978
- Pat Morita
- Â Moby 1 episode, 1978
- Anthony James
- Â Summersday 1 episode, 1978
- Noble Willingham
- Â Artemus Washburn 1 episode, 1977
- Lawrence Pressman
- Â Cmdr. Phil Roth 1 episode, 1977
- Annette Charles
- Â Ginny Mendoza 1 episode, 1977
- Ahna Capri
- Â Louisa 1 episode, 1977
- Sydney Lassick
- Â Smith 1 episode, 1977
- Harvey Jason
- Â Dashki 1 episode, 1977
- Burr DeBenning
- Â Chazz / ... 1 episode, 1977
- Dennis Redfield
- Â Dick Stoneman 1 episode, 1977
- Lisa Blake Richards
- Â Jenny Reynolds 1 episode, 1977
- Brad David
- Â Sid 1 episode, 1977
- Jack Somack
- Â Encyclopedia salesman 1 episode, 1977
- James Brodhead
- Â Trubshawe 1 episode, 1977
- Tina Lenert
- Â Click One 1 episode, 1977
- James Ingersoll
- Â Officer 1 episode, 1978
- Tony Urbano
- Â Oscar 1 episode, 1978
- Arlene Martel
- Â Carla 1 episode, 1977
- Timothy Scott
- Â Caine 1 episode, 1977
- Norman Snow
- Â Tybalt 1 episode, 1977
- Gary Owens
- Â Blaise Mullen 1 episode, 1977
- Mark Jenkins
- Â Lt. Ainsley 1 episode, 1977
- Stanley Bennett Clay
- Â Boy 1 episode, 1977
- Michael Alaimo
- Â Cab Driver 1 episode, 1977
- Carole Demas
- Â Pamela 1 episode, 1977
- Flip Reade
- Â Click Two 1 episode, 1977
- Victoria Huxtable
- Â Juliette Schubert 1 episode, 1977
- Eugenia Wright
- Â Trivi 1 episode, 1978
- Mel Scott
- Â Bert Davis 1 episode, 1978
- Steve Franken
- Â Doctor 1 episode, 1977
- Lewis Arquette
- Â Friar Laurence 1 episode, 1977
- Bill Zuckert
- Â Virgil 1 episode, 1977
- Frank Bonner
- Â Bartender 1 episode, 1977
- Whitney Rydbeck
- Â Click Three 1 episode, 1977
- Monte Landis
- Â Maitre'D 1 episode, 1977
- Carole Mallory
- Â Vicki 1 episode, 1977
- Ivan Bonar
- Â Edwin Shirley 1 episode, 1977
- Alan Mandell
- Â Grant Stockwood 1 episode, 1977
- Carol Miyaoka
- Â Siren 1 episode, 1977
- Lyman Ward
- Â Clavius 1 episode, 1978
- Donna Garrett
- Â Student 1 episode, 1978
- Yabo Obien
- Â Toba 1 episode, 1978
- James Sikking
- Â Colonel Manzone 1 episode, 1977
- Paul Mantee
- Â FBI Agent Fuller 1 episode, 1977
- Joshua Bryant
- Â Dr. Doug Berkley 1 episode, 1977
- Raf Mauro
- Â Maitre D' 1 episode, 1977
- Scott Porter
- Â Mercutio 1 episode, 1977
- Hanns Manship
- Â Policeman 1 episode, 1977
- Larry Breeding
- Â Buddy O'Toole 1 episode, 1978
- Allen Case
- Â Lt. Cmdr. Johnson 1 episode, 1977
- William Glover
- Â Prince Escalus 1 episode, 1977
- Hank Stohl
- Â Sub Captain Wes 1 episode, 1977
- Gary Tomlin
- Â Cetacean crew 1 episode, 1977
- Garrett Craig
- Â Chauffer 1 episode, 1977
- Pat Paris
- Â Woman on beach with note 1 episode, 1977
- William 'Billy' Benedict
- Â Guard 1 episode, 1978
- Virginia Gregg
- Â Whale Scientist 1 episode, 1977
- Arthur Batanides
- Â Police Detective 1 episode, 1977
- Kim Lankford
- Â Cetacean crew 1 episode, 1977
- Russell Arms
- Â Medical Examiner 1 episode, 1977
- David Gautreaux
- Â Sampson 1 episode, 1977
- Penelope Willis
- Â Cetacean crew 1 episode, 1977
- Nancy Dalziel
- Â Woman at Bar 1 episode, 1977
- Harvey J. Goldenberg
- Â Man 1 episode, 1978
- Curt Lowens
- Â Emil 1 episode, 1977
- Rick Goldman
- Â Security Guard at dock 1 episode, 1977
- Arch Archambault
- Â Second Officer 1 episode, 1977
- Ed Penny
- Â Henchman 1 episode, 1977
- Allen Joseph
- Â Proprietor 1 episode, 1978
- Bob Minor
- Â Minion 1 episode, 1977
- Charles Davis
- Â British Scientist 1 episode, 1977
- Lilyan Chauvin
- Â French Scientist 1 episode, 1977
- Ric Drasin
- Â Minion 1 episode, 1977
- Vince Deadrick Sr.
- Â Herb Wayland 1 episode, 1977
- Rozelle Gayle
- Â Conrad 1 episode, 1977
- Maurice Hill
- Â Lou 1 episode, 1977
- Vincent Milana
- Â American Scientist 1 episode, 1977
- Frank Martone
- Â Minion 1 episode, 1977
- Alex Rodine
- Â Russian Scientist 1 episode, 1977
- Joel Lawrence
- Â Hot Tub Manager 1 episode, 1977
- James Faracci
- Â Minion 1 episode, 1977
- Philip Baker Hall
- Â George 1 episode, 1977
- Jim Morris
- Â Minion 1 episode, 1977
- Maralyn Thoma
- Â Myrtle 1 episode, 1977
- Ernie Hudson
- Â Minion 1 episode, 1977
- Dick Winslow
- Â Fish Store Clerk 1 episode, 1977
- Marguerite DeLain
- Â First Receptionist 1 episode, 1977
- Anthony Pearson
- Â Minion 1 episode, 1977
- Trudy Marshall
- Â Woman at Party 1 episode, 1977
- Julius LeFlore
- Â Minion 1 episode, 1977
- Jim Tarleton
- Â Minion 1 episode, 1977
- Robert Dore
- Â Diver 1 episode, 1977
- Michael Watson
- Â Diver 1 episode, 1977
- Connie Izay
- Â First Nurse 1 episode, 1977
- Judd Laurance
- Â Intern 1 episode, 1977
- James Chandler
- Â Man on Beach 1 episode, 1977
- Patricia Anderson
- Â Second Receptionist 1 episode, 1977
- Akemi Kikumura
- Â Third Receptionist 1 episode, 1977
- Larry Holt
- Â Ambulance Driver 1 episode, 1977
- Peter Weiss
- Â Test Lab Technician 1 episode, 1977
- Robert Phalen
- Â Habitat Technician 1 episode, 1977
- Maralyn Thuma
- Â Second Nurse 1 episode, 1977
- Philip Roye
- Â Intern 1 episode, 1977
- Cheryl Robinson
- Â X-Ray Technician 1 episode, 1977
- Scott Stevensen
- Â Boy on Beach 1 episode, 1977
- Philip Tanzini
- Â Boy at Phone Booth 1 episode, 1977
- Dee Wallace
- Â Hot Dog Stand Owner 1 episode, 1977
- Brian Baker
- Â Sub Navigator (uncredited) 2 episodes, 1977
- Gene LeBell
- Â Ditcher (uncredited) 1 episode, 1977
- Mike Douglas
- Â Newscaster (uncredited) 1 episode, 1977
- Ivor Francis
- Â Dr. Medlow (uncredited) 1 episode, 1977
- John Dennis
- Â Bartender (uncredited) 1 episode, 1977
- Lisa Pera
- Â Mother (uncredited) 1 episode, 1977
- Eddie Garrett
- Â Technician (uncredited) 1 episode, 1977
- Ruth Manning
- Â Clara (uncredited) 1 episode, 1977
- George Sawaya
- Â Schubert crewman (uncredited) 1 episode, 1977
- Tony Epper
- Â Hollister's Henchman (uncredited) 1 episode, 1977
- Russ Dodson
- Â Constable (uncredited) 1 episode, 1977
- Peter Kwong
- (uncredited) 1 episode, 1978
- Michael Swan
- Â Officer (uncredited) 1 episode, 1978