Dermot Walsh
— Guy Thornton
Hazel Court
— Margaret Thornton
Joss Ambler
— Yacht Port Manager
Hugh Burden
— Dr. Fawcett
Mignon O'Doherty
— Mrs. Manley
Hugh Latimer
— Peter
Joan Carol
— Mrs. Martineau
John Robinson
— Prof. Martineau / Mansel
Joss Ackland
— Ron, 2nd Fisherman
John King-Kelly
— Sid, 3rd Fisherman
Laidman Browne
— Coroner
Meadows White
— Mr. Leech, Surveyor
Patricia Owens
— Party Girl (Joyce)
Melissa Stribling
— Party Girl (Vera)
Ian Carmichael
— Bernard
Geoffrey Dunn
— Strange Passenger
Pat McGrath
— Bert, 1st Fisherman