"Flirtatious mermaid Miranda swaps places with a schoolteacher who has gone on holiday. All is well until she falls in love with a human."
Glynis Johns
as Caroline Trewella / Miranda Trewella
Donald Sinden
as Jeff Saunders
Anne Crawford
as Barbara Davenport
Margaret Rutherford
as Nurse Carey
Dora Bryan
as Berengaria
Nicholas Phipps
as Col. Barclay Sutton
Peter Martyn
as Ronald Baker
Noel Purcell
as Percy
Joan Hickson
as Mrs. Forster
Judith Furse
as Viola
Irene Handl
as Mme. Blanche
David Hurst
as Signor Mantalini
Martin Miller
as Dr. Fergus
Deryck Guyler
as Editor
Anthony Oliver
as Pawnbroker
Lawrence Ward
as Alphonse
Martin Boddey
as Marco (uncredited)
Stringer Davis
as The Vicar (uncredited)
Meredith Edwards
as Police Constable (uncredited)
Lucy Griffiths
as Dr. Fergus' Secretary (uncredited)
John Horsley
as Sports Organiser (uncredited)
Dandy Nichols
as Nurse Carey's Landlady (uncredited)
George Woodbridge
as Fisherman Outside Pub (uncredited)
as Police Constable
Benjamin Frankel
Original Music Composer
Betty E. Box
Producer
Ernest Steward
Director of Photography
Ralph Thomas
Director
Peter Blackmore
Screenplay
Story
H. A. R. Thomson
Camera Operator
George Provis
Art Direction
Biddy Chrystal
Hairstylist
Gerald Thomas
Editor
Gordon K. McCallum
Sound Recordist
Earl St. John
Executive Producer
Joan Ellacott
Costume Design
Denis Holt
Production Manager
James H. Ware
Assistant Director
John Dennis
Peter Boita
Sound Editor
W.T. Partleton
Makeup Artist