• Starring: Patrick Duffy (Mark Harris), Belinda J. Montgomery (Dr. Elizabeth Merrill), Dean Santoro (Ernie Smith), Art Lund (Admiral Dewey Pierce)
• And: Victor Buono (Mr. Schubert)
• Guest Stars: Lawrence Pressman (Commander Phil Roth), Mark Jenkins (Lieutenant Ainsley), Steve Franken (Doctor), Joshua Bryant (Dr. Doug Berkley), Allen Case (Lieutenant Commander Johnson)
• Featuring: Virginia Gregg (Whale Scientist), Curt Lowens (Emil), Charles Davis (British Scientist), Lilyan Chauvin (French Scientist), Vincent Milana (American Scientist), Alex Rodine (Russian Scientist), Philip Baker Hall (George), Marguerite DeLain (First Receptionist), Trudy Marshall (Woman at Party), Michael J. London (Popeye), Robert Dore (Diver), Michael Watson (Diver), Connie Izay (First Nurse), Judd Laurance (Intern), Jim Chandler (Man on Beach), Patricia Anderson (Second Receptionist), Akemi Kikumura (Third Receptionist), Larry Holt (Ambulance Driver), Peter Weiss (Test Lab Assistant), Robert Phalen (Habitat Technician), Maralyn Thuma (Second Nurse), Phillip Roye (Intern), Cheryl Robinson (X-Ray Technician), Scott Stevenson (Boy on Beach), Philip Tanzini (Boy at Phone Booth)
• Written By: Mayo Simon
• Directed By: Lee H. Katzin

• Starring: Patrick Duffy (Mark Harris), Belinda J. Montgomery (Dr. Elizabeth Merrill), Kenneth Tigar (Dr. Miller Simon), Alan Fudge (C.W. Crawford, Jr.)
• Guest Stars: Tiffany Bolling (Lioa / Dilly), Burr DeBenning (Xos / Chazz)
• Featuring: Stanley Clay (Boy), Alan Mandell (Grant Stockwood), Annette Cardona (Ginny Mendoza), Hank Stohl (Sub Captain Wes), Russell L. Arms (Medical Examiner), Arch Archambault (Second Officer), Michael J. London (Air Lock Man), Vincent Deadrick (Herb Wayland), Maurice Hill (Lou), Joel Lawrence (Hot Tub Manager), Maralyn Thoma (Myrtle), Dick Winslow (Fish Store Clerk)
• Written By: Robert Lewin
• Directed By: Marc Daniels

• Starring: Patrick Duffy (Mark Harris), Belinda J. Montgomery (Dr. Elizabeth Merrill), Kenneth Tigar (Dr. Miller Simon), Alan Fudge (C.W. Crawford, Jr.)
• Co-Starring: Fred Beir (Sub Captain), Brad David (), Carol Demas ()
• Featuring: Ivan Bonar (Edwin Shirley), James B. Sikking (Colonel Manzone), Erik Holland (), James R. Parkes ()
• Written By: John D.F. Black
• Directed By: Reza Badiyi

• Starring: Patrick Duffy (Mark Harris), Belinda J. Montgomery (Dr. Elizabeth Merrill), Kenneth Tigar (Dr. Miller Simon), Alan Fudge (C.W. Crawford, Jr.)
• Guest Stars: Darleen Carr (Dr. Mary Smith), Dennis Redfield (Dick Redstone)
• And: Pamela Peters Solow (Jane Smith)
• Co-Starring: Fred Beir (Sub Captain), Paul Mantee ()
• Featuring: Michael Jay London (), Arthur Batanides (), Rick Goldman ()
• The Minions: Bob Minor, Ric Drasin, James Fraracci, Ernie Hudson, Julius Le Flore, Frank Martone, Jim Morris, Anthony Pearson, Jim Tarleton
• Teleplay By: Luthor Murdoch
• Story By: Jerry Sohl
• Directed By: Charles S. Dubin

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Co-Starring: Robert Lussier (Brent)
• Special Appearance By: Victor Buono (Mr. Schubert), James Brodhead (Trubshawe)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Written By: Tom Greene
• Directed By: Virgil Vogel

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Special Appearance By: Victor Buono (Mr. Schubert)
• Co-Starring: Robert Lussier (Brent), Jack Somack ()
• Featuring: Duncan Gamble ()
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Brandyn Artise ()
• Written By: Alan Caillou
• Directed By: Virgil Vogel

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Special Appearance By: Victor Buono (Mr. Schubert)
• Co-Starring: Robert Lussier (Brent), Sydney Lassick (Smith), Vicky Huxtable (Juliette Schubert), Carole Mallory (Vicki)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Teleplay By: Luthor Murdoch
• Story By: David Balkan
• Directed By: Harry Harris

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Star: Ted Neeley (Jack Muldoon)
• Special Guest Star: Kareem Abdul-Jabbar (Thark)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Written By: Michael Wagner
• Directed By: Richard Benedict

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Special Appearance By: Victor Buono (Mr. Schubert)
• Guest Stars: Robert Lussier (Brent), Harvey Jason (Dashki), Gary Owens (Blaise Mullen)
• Co-Starring: Monte Landis (Maitre'D)
• Featuring: Hanns Manship (Policeman), Pat Paris ()
• Written By: Larry Alexander
• Directed By: Michael O'Herlihy

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Stars: Pernell Roberts (Clint Hollister), Jamie Smith Jackson (Bettina Washburn)
• Co-Starring: Noble Willingham (Artemus Washburn), Tasha Martell (), Bill Zuckert (Virgil)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Written By: Luther Murdoch
• Directed By: Barry Crane

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Special Appearance By: Victor Buono (Mr. Schubert)
• Guest Star: Rene Auberjonois (Havergal)
• Special Guest Stars: Tina Lenert (Click One), Flip Reade (Click Two), Whitney Rydbeck (Click Three)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Penelope Willis (), Brandyn Artise ()
• With: Rozelle Gayle (Conrad)
• Written By: Larry Alexander
• Directed By: David Moessinger

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Stars: Lisa Eilbacher (Juliet), John Shea (Romeo), Ahna Capri ()
• Co-Starring: Norman Snow (Tybalt), Lewis Arquette (Friar Laurance), Scott Porter (Mercutio), William Glover ()
• Featuring: David Gautreaux ()
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Written By: Stephen Kandel
• Directed By: Robert Douglas

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Stars: Michele Carey (Belle), Val Avery (Lew)
• And: Pamela Peters (Sara)
• Featuring: Michael Alaimo (), Frank Bonner (Bartender), Ralph Mauro (), Garrett Craig (), Nancy Dalziel (), Ed Penny ()
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane)
• Written By: Stephen Kandel
• Directed By: Dann Cahn

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Stars: Ted Neeley (Jack Muldoon), Ted Cassidy (Canja), Tony Urbano (Oscar)
• Co-Starring: Eugenia Wright (Trivi)
• Featuring: Yabo Obien (Toba)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane)
• Written By: Peter Alan Fields
• Directed By: David Moessinger

• Starring: Patrick Duffy (Mark), Belinda J. Montgomery (Elizabeth), Alan Fudge (C.W.)
• Guest Star: Dick Gautier (Duke)
• Special Guest Star: Pat Morita (Moby)
• Co-Starring: James Ingersoll (Officer), Mel Scott (Bert Davis), Lyman Ward (Clavius), Larry Breeding (Buddy O'Toole)
• Featuring: William Benedict (Guard), Harvey J. Goldenberg (), Allen Joseph (Proprietor)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), J. Victor Lopez (Chuey), Jean Marie Hon (Jane), Anson Downes (Alan)
• Written By: Shimon Wincelberg
• Directed By: Paul Krasny

• Starring: Patrick Duffy (Mark), Alan Fudge (C.W.)
• Guest Stars: Neville Brand (Stringer), Laurette Spang (Amanda Trevanian)
• Special Guest Stars: Michael Strong (Hugh Trevanian), Lisa Richards (Jenny Reynolds)
• Co-Starring: Timothy Scott (Caine)
• Featuring: Carol Miyaoka (Siren)
• The Crew of "Cetacean": Richard Laurance Williams (Jomo), Gary Tomlin (Helmsman), Kim Lankford (), J. Victor Lopez (Chuey)
• Written By: Michael Wagner
• Directed By: Edward Abroms

• Starring: Patrick Duffy (Mark), Alan Fudge (C.W.)
• Guest Stars: Sharon Farrell (Charlene Baker), Billy Barty (Moxie), Anthony James (Summersday)
• Featuring: Sandy Barry (), Gino Baffa (), Donna Garrett (Student), Sean Morgan ()
• Written By: Larry Alexander
• Directed By: Dennis Donnelly