The Reichsmarine was the name of the German Navy during the Weimar Republic and first two years of Nazi Germany. It was the naval branch of the Reichswehr, existing from 1919 to 1935. In 1935, it became known as the Kriegsmarine, a branch of the Wehrmacht; a change implemented by Adolf Hitler. Many of the administrative and organizational tenets of the Reichsmarine were then carried over into the organization of the Kriegsmarine.

The Weimar Republic, officially known as the German Reich, was a historical period of Germany from 9 November 1918 to 23 March 1933, during which it was a constitutional federal republic for the first time in history; hence it is also referred to, and unofficially proclaimed itself, as the German Republic. The period's informal name is derived from the city of Weimar, which hosted the constituent assembly that established its government. In English, the republic was usually simply called "Germany", with "Weimar Republic" not commonly used until the 1930s.