Bradford Dillman

Paul Grogan

Heather Menzies

Maggie McKeown

Kevin McCarthy

Dr. Robert Hoak

Keenan Wynn

Jack

Dick Miller

Buck Gardner

Barbara Steele

Dr. Mengers

Belinda Balaski

Betsy

Melody Thomas Scott

Laura Dickinson

Bruce Gordon

Colonel Waxman

Barry Brown

Trooper

Paul Bartel

Mr. Dumont

Richard Deacon

Earl Lyon

Janie Squire

Barbara Randolph

Bill Smillie

Jailer

Diamond Farnsworth

Water-skier

Bruce Paul Barbour

Man in Boat

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)