- Ralph Byrd
- Lt. Terry Kent
- Bela Lugosi
- Boroff
- Maxine Doyle
- Jean Norman
- Richard Alexander
- Thorg
- Lee Ford
- Snapper McGee
- Herbert Rawlinson
- Cmdr. Boyle
- John Picorri
- G.A. Rackerby [Chs. 2-12]
- Lawrence Grant
- Rabinisi - Boroff's Spokesman at Screening [Ch. 1]
- Thomas Carr
- Ens. Jim Kent [Ch. 1]
- Carleton Young
- Henchman Dodds [Ch. 4]
- Allen Connor
- Dick Norman
- George Chesebro
- L.H. Degado - Chief Thug [Ch. 5]
- Ranny Weeks
- Wies - Ambulance Orderly Thug [Ch. 4]
- Roy Barcroft
- Goebel
- Richard Beach
- Seaman
- Earle D. Bunn
- Kelp Plant Heavy 1
- Yakima Canutt
- Seaman
- Steve Carruthers
- Wireless Operator
- Ed Cassidy
- Capt. Johnson
- Jack Rube Clifford
- Carver
- Baldwin Cooke
- Seaman
- Floyd Criswell
- Motorcycle Heavy
- Jack Daley
- S.S. Carfax Captain
- Leon Davidson
- Seaman
- Forrest Dillon
- Sea Wolf Thug
- Lester Dorr
- Hospital Radium-Tech
- Curley Dresden
- Dock Heavy 1
- Robert Dudley
- Pierport Station Agent
- Norwood Edwards
- Seaman
- Frank Ellis
- Kelp Plant Worker
- Frank Fanning
- Roadside Police Sergeant
- Jerry Frank
- Sea Wolf Thug
- Lee Frederick
- Citizen
- Audrey Gaye
- Phone Switchboard Supervisor
- Joseph W. Girard
- Cmdr. Green
- Kit Guard
- Kelp Plant Heavy 2
- Henry Hale
- Krohn
- Sam Harris
- Emissary
- Jack Ingram
- Seaman
- Warren Jackson
- Boat Heavy #4
- Payne B. Johnson
- Boy in Lifeboat
- Jerry Larkin
- Henchman
- Rex Lease
- Coast Guard Orderly
- Alexander Leftwich
- Froman
- Jack Long
- Seaman
- Joseph P. Mack
- S.S. Adamic Captain
- Teddy Mangean
- Seaman
- Gene Marvey
- Blake
- Frankie Marvin
- Sniper
- Frank Meredith
- Cop
- James Millican
- Dock Heavy 4
- Pat Mitchell
- Radioman
- King Mojave
- Ambulance Driver-Thug
- Edwin Mordant
- Dr. Meade
- Michael Morgan
- Moore - Coast Guardsman
- Henry Morris
- Dock Heavy 2
- Charles Murphy
- S.S. Adamic Mate
- John Mustill
- Policeman
- Henry Otho
- S.S.'Carfax Mate
- Eddie Phillips
- Boat Heavy 1
- Loren Riebe
- Pete
- Vinegar Roan
- Dock Heavy 3
- Jack Roberts
- Jones
- Buddy Roosevelt
- Patrol Boat Lt. Scott
- Dick Scott
- Gang Launch Pilot
- Reed Sheffield
- Thug Loading Launch
- Dick Sheldon
- Ambulance Attendant-Thug
- Harry Strang
- Phone Company Code Expert
- Duke Taylor
- Loader
- Tom Ung
- Charlie
- Billie Van Every
- Phone Operator
- Robert Walker
- Black
- Frank Wayne
- Payne
- Herbert Weber
- Belden
- Robert J. Wilke
- Seaman
- Robert B. Williams
- Sloan
- Roger Williams
- Black
- Dan Wolheim
- Capt. Slauson
- Duke York
- Sea Heavy #1
