Flakavatnet is an alpine lake on the border of Vestland and Buskerud counties in Norway. The 3.43-square-kilometre (1.32 sq mi) lake lies in the municipalities of Ulvik (in Vestland) and Hol (in Viken) and the lake lies entirely within the Hallingskarvet National Park. The village of Finse lies about 5 kilometres (3.1 mi) southwest of the lake.

The lake is one of the largest lakes in Europe that lies in the transition to the high-alpine zone, where vegetation is minimal or absent and influence of permanent snow patches and glaciers are evident.