SS Prinz Eitel Friedrich was a German passenger liner which saw service in the First World War as an auxiliary cruiser of the Imperial German Navy and named after Prince Eitel Friedrich of Prussia. Though largely overlooked, Prinz Eitel Friedrich was, after SS Kronprinz Wilhelm, the most successful of Germany's first wave of auxiliary cruisers. She was able to remain at large for seven months, from August 1914 to March 1915, and sank 11 ships, for a total tonnage of 33,000 GRT.