William Holden as Capt. David Ross

Sophia Loren as Stella

Trevor Howard as Capt. Chris Ford

Bernard Lee as Cmdr. Wadlow

Oskar Homolka as Van Dam

Kieron Moore as Kane

Noel Purcell as Hotel Clerk

Bryan Forbes as Weaver

Beatrix Lehmann as Housekeeper

Rupert Davies as Baker

Russell Waters as Sparks

Sidney Vivian as Grogan

Irene Handl as Clerk

John Crawford as American Captain

Jameson Clark as English Captain

Guy Standeven as Policeman (uncredited)

Keith Faulkner as Signalman (uncredited)

Michael Caine as Seaman (uncredited)

Bart Allison as Seaman on W88 (uncredited)

Belita as Canteen Hostess (uncredited)

Pauline Chamberlain as Woman Dancing at Forces Centre (uncredited)

Keith Faulkner as Seaman on W88 (uncredited)

Renée Houston as Canteen Worker (uncredited)

Richard Neller as Officer in Operations Room (uncredited)

Ernie Rice as Officer in Operations Room (uncredited)

Robert Rietti as Dubbing (voice) (uncredited)

John Tatham as Salvage Unit Captain (uncredited)

Reg Thomason as Soldier at Dance (uncredited)