Lake Syamozero (Russian: Сямозеро, Finnish: Säämäjärvi, Karelian: Seämärvi) is a large freshwater lake in the Republic of Karelia, northwestern part of Russia.

It is located west of Petrozavodsk, the capital of the Republic, and has an area between 265 and 270 km2.

Syamozero is used for fishery, water transport and timber rafting.

On June 18, 2016, 14 children died when a storm caught a tour group on the lake.

[1][2][3] Four people have been arrested on suspicion of safety violations as there had been repeated warnings days prior of an impending storm and advising against boating on the lake.