Jock Mahoney

as Commander Harold 'Alan' Roberts

Shirley Patterson

as Margaret 'Maggie' Hathaway

William Reynolds

as Lt. Jack Carmen

Henry Brandon

as Dr. Carl Hunter

Douglas Kennedy

as Capt. Burnham

Phil Harvey

as Machinist's Mate Steve Miller

Kenner G. Kemp

as Officer at Briefing / Officer on Ship (uncredited)

Bing Russell

as Radio Operator (uncredited)