Thunder Afloat

Wallace Beery

John Thorson

Chester Morris

'Rocky' Blake

Virginia Grey

Susan Thorson

Douglass Dumbrille

District Commander

Carl Esmond

U-Boat Captain

Clem Bevans

'Cap' Finch

John Qualen

Milo

Regis Toomey

Ives

Henry Victor

German U-Boat Officer

Addison Richards

Admiral Ross

Hans Joby

U-Boat Petty Officer

Henry Hunter

Ensign Dyer

Jonathan Hale

Admiral Girard

Leon Ames

Recruiting Officer (uncredited)

Arthur Belasco

Fisherman (uncredited)

Joseph E. Bernard

Fisherman (uncredited)