The Lake Omladinsko jezero or lake of Youth is located in the area of the Gorski Kotar in Croatia.

It was formed during the construction of a stopping with an aim of feeding a Hydroelectric station. Its surface is 2 km ² and its 40 meters depth.

Surrounded by wooded hills of Coniferous S, in a site of a great beauty, the lake became a tourist site very visited in summer as in winter.