Don Knotts

Henry Limpet

Carole Cook

Bessie Limpet

Jack Weston

George Stickel

Andrew Duggan

Harlock

Larry Keating

Admiral P.P. Spewter

Oscar Beregi Jr.

Nazi Admiral (as Oscar Beregi)

Charles Meredith

Fleet Admiral

Elizabeth MacRae

Ladyfish (voice)

Paul Frees

Crusty (voice)

Phil Arnold

Short Fisherman (uncredited)

Al Checco

Sailor (uncredited)

Sayre Dearing

Passerby/Naval Officer at Meeting (uncredited)

Louie Elias

Sailor (uncredited)

George Holmes

Scientist (uncredited)

Mike Lally

Naval Officer at Meeting (uncredited)

Harold Miller

Officer at Fleet Admiral's Briefing (uncredited)

Charles Morton

Boat Captain (uncredited)

Scott Seaton

Old Man in Shipping Office (uncredited)

Feridun Çölgeçen

Scientist (uncredited)

Peter Adams

Lieutenant (uncredited)