Bradford Dillman
Paul Grogan
Heather Menzies
Maggie McKeown
Kevin McCarthy
Dr. Robert Hoak
Barbara Steele
Dr. Mengers
Melody Thomas Scott
Laura Dickinson
Bruce Gordon
Colonel Waxman
Shannon Collins
Suzie Grogan
Janie Squire
Barbara Randolph
Jack Pauleson
Boy in Canoe
Eric Henshaw
Father in Canoe
Diamond Farnsworth
Water-skier
Bruce Paul Barbour
Man in Boat
Sally Bondi
Swimming Deb (uncredited)
Eric Braeden
Dr. Robert Hoak (swimming double) (uncredited)
Joe Dante
Scuba Diver #2 (uncredited)
Amy Holden Jones
Hertz Clerk (uncredited)
Andrew G. La Marca
Scuba Diver #1 (uncredited)
John Sayles
Army Sentry (uncredited)
Phil Tippett
Scuba Diver (uncredited)