Coordinates: 60°35′N 28°31′E / 60.583°N 28.517°E
Vyborg Bay (Russian: Выборгский залив, Finnish: Viipurinlahti, Swedish: Viborgska viken) is a deep inlet running northeastward near the eastern end of Gulf of Finland in the Baltic Sea. The city of Vyborg is located near the head of the gulf.
The bay is connected by the Saimaa Canal to the lake Saimaa in Finland.
In 1790 the bay was the scene of one of the largest naval battles in history, the Battle of Vyborg Bay with a total of 498 Russian and Swedish ships.
The end of the bay is called Zashchitnaya Bay (Russian: бухта Защитная, Finnish: Suomenvedenpohja. In the Middle Ages the river Vuoksi had an outlet there, which however dried up little by little due to post-glacial rebound and was left completely dry in 1857 when the Kiviniemi rapids in Losevo (Russian: Лосево, Finnish: Kiviniemi), Karelian isthmus were formed and the Burnaya River became the main outlet of Vuoksa.