Trailer
Images
 | Rex Reason as Dr. Thomas Morgan |
 | Jeff Morrow as Dr. William Barton |
 | Leigh Snowden as Marcia Barton |
 | Gregg Palmer as Jed Grant |
 | Maurice Manson as Dr. Borg |
 | James Rawley as Dr. Johnson |
 | David McMahon as Capt. Stanley |
 | Paul Fierro as Morteno |
 | Lillian Molieri as Mrs. Morteno |
 | Frank Chase as Steward |
 | Larry Hudson as State Trooper |
 | Ricou Browning as The Gill Man (in water)(uncredited) |
 | Don Megowan as The Gill Man (on land)(uncredited) |
 | George Sowards as Ranch Hand (uncredited) |
| Directing | |
| John Sherwood | Director |
Visual Effects | |
| Clifford Stine | Visual Effects |
Sound | |
| Peter Berkos | Sound Editor |
Visual Effects | |
| Clifford Stine | Visual Effects Camera |
Sound | |
| Leslie I. Carey | Sound |
| George Hoagland | Sound Editor |
| Robert Pritchard | Sound |
Costume & Make-Up | |
| Jay A. Morley Jr. | Costume Design |
Sound | |
| Robert L. Bratton | Sound Editor |
Costume & Make-Up | |
| Roger J. Weinberg | Costume Design |
| Jack Kevan | Makeup Effects Designer |
Production | |
| William Alland | Producer |
Art | |
| Robert Emmet Smith | Art Direction |
| Alexander Golitzen | Art Direction |
Sound | |
| Heinz Roemheld | Original Music Composer |
Writing | |
| Arthur A. Ross | Screenplay |
| Arthur A. Ross | Story |
Editing | |
| Edward Curtiss | Editor |
Sound | |
| Henry Mancini | Original Music Composer |
Costume & Make-Up | |
| Vincent Romaine | Makeup Artist |
Camera | |
| Maury Gertsman | Director of Photography |
Art | |
| John P. Austin | Set Decoration |
| Russell A. Gausman | Set Decoration |
Sound | |
| Irving Gertz | Original Music Composer |
Costume & Make-Up | |
| Joan St. Oegger | Hairstylist |
| Bud Westmore | Makeup Supervisor |
Camera | |
| Eddie Pyle | Camera Operator |
| Lew Swartz | Assistant Camera |
Art | |
| Julius Rosenkrantz | Props |
