SS Rio de Janeiro was a German cargo steamship, owned by the Hamburg Südamerikanische shipping company and registered in Hamburg. She was built as Santa Ines in 1914, and renamed Rio de Janeiro in 1921. Until World War II she carried passengers and freight between Germany and South America. On 7 March 1940 Nazi Germany's Kriegsmarine requisitioned her to carry troops and equipment, before Operation Weserübung, the invasion of Norway and Denmark, began on 9 April 1940.