• 
  Joe Dante

  regizor

• 
  John Sayles

  scenarist

• 
  Heather Menzies

  Maggie McKeown
• 
  Kevin McCarthy

  Dr. Robert Hoak
• 
  Bradford Dillman

  Paul Grogan
• 
  Keenan Wynn

  Jack
• 
  Phil Tippett

  Scuba Diver #3 (victim)
• 
  Joe Dante

  Scuba Diver #2

• 
  John Sayles

  Army Sentry
• 
  Amy Holden Jones

  Hertz Clerk
• 
  Andrew G. La Marca

  Scuba Diver #1
• 
  Bruce Gordon

  Colonel Waxman
• 
  Eric Braeden

  Dr. Robert Hoak (swimming double)
• 
  Barbara Steele

  Dr. Mengers
• 
  Melody Thomas Scott

  Laura Dickinson

• 
  Dick Miller

  Buck Gardner
• 
  Paul Bartel

  Mr. Dumont
• 
  Richard Deacon

  Earl Lyon
• 
  Belinda Balaski

  Betsy
• 
  Barry Brown

  Trooper
• 
  Shannon Collins

  Suzie Grogan
• 
  Shawn Nelson

  Whitney
• 
  Janie Squire

  Barbara Randolph