The Battle of the Gulf of Riga was a World War I naval operation of the German High Seas Fleet against the Russian Baltic Fleet in the Gulf of Riga in the Baltic Sea in August 1915. The operation's objective was to destroy the Russian naval forces in the Gulf and facilitate the fall of Riga to the German army in the later stages of the Central Powers' offensive on the Eastern Front in 1915. The German fleet, however, failed to achieve its objective and was forced to return to its bases; Riga remained in Russian hands until eventually falling to the Germans on 1 September 1917.