- Pat O'Brien
- Mike Farrough
- Constance Bennett
- Christine Blaine
- John Halliday
- John Morgan
- Alan Baxter
- Larry Perrin, alias Larry Ross
- Erwin Kalser
- Dr. Adolph Behrens
- Edgar Buchanan
- Charles Atterbee
- Frank Sully
- Tommy Malone
- Marjorie Gateson
- Mrs. Winslow
- Francis Pierlot
- Professor Mudge
- Jessie Busley
- Mrs. Mudge
- Melville Cooper
- Ship's Mate Penney
- Stanley Logan
- Captain James P. Hollister
- Leslie Denison
- Ship's Mate Jones
- Don Beddoe
- Ship's Chief Engineer Anderson
- Hans Schumann
- Submarine Commander
- Norbert Schiller
- Submarine First Officer
- Frank Alten
- Submarine Radio Operator
- Bruce Bennett
- Ship's gunnery officer
- Rex Post
- First Mate
- Dick Rich
- Perrin's Henchman at Dock
- Olaf Hytten
- Agent
- Arthur Mulliner
- Detective
- Frank Baker
- Detective
- Frank Benson
- Sailor
- Bobbie Hale
- Sailor
- Fred Wolff
- German Sailor
- Douglas Gordon
- Ship's Lookout
- Jean Prescott
- Mrs. Hollister
- Hans von Morhart
- German Sailor
- Paul Michael
- German Sailor
- Wyndham Standing
- Man
- Arno Frey
- Submarine Gunner
- David Dunbar
- Sailor
- James Kilgannon
- Sailor
