| Basil Rathbone | Sherlock Holmes |
| Nigel Bruce | Dr. John H. Watson |
| Marjorie Riordan | Sheila Woodbury |
| Rosalind Ivan | Agatha Dunham |
| Morton Lowry | Sanford aka Prince Nikolas - Ship's Steward |
| Leslie Vincent | Nikolas Watson |
| Martin Kosleck | Mirko |
| Rex Evans | Gregor |
| John Abbott | Jodri |
| Gerald Hamer | Kingston |
| Director | Roy William Neill |
| Producer | Howard Benedict; Roy William Neill |
| Writer | Arthur Conan Doyle; Leonard Lee |
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