Wdzydze, also known as the Kashubian Sea, Big Water and Szerzawa, is a lake in the Tuchola Forest in the Kościerzyna County, in the region of South Kashubia. The lake is part of a system of linked lakes, comprising Wdzydze, Radolne, Gołuń, Jelenie, and Słupinko. The whole lake is part of the Wdzydze Landscape Park.