Kozjak Lake

Kozjak Lake is Plitvice Lakes National Park's largest lake, sitting between the Upper Lakes and the Lower Lakes canyon. It works best as part of a longer circuit. Keep an electric boat crossing in your plan if you can: it breaks up the walking and gives you a quiet view across the water.

The park's longer K1 and K2 routes follow the western shore and return along the eastern shore after a short electric-boat ride. Other marked programs use the crossing too. The boat is included with a valid park ticket, but the route around it still means several hours of walking, so choose the whole circuit for the day you want.

At P1, the park rents rowboats for up to four people. Rowing is allowed; swimming is prohibited in every lake in the park. The electric boat is the easier way to cross as part of a route, while a rowboat lets you explore at your own pace and is a separate paid activity.

Kozjak was once two lakes. About 400 years ago, one tufa barrier sank below the surface and the basins joined. On a sunny day, the park says you can see the submerged barrier from the electric boat. Look down as you cross; it is a more unusual picture than another wide shot of water and trees.

Plitvice's lakes began forming about 12,000 to 15,000 years ago as tufa barriers built up and changed the courses of water and waterfalls. Water dissolves carbonate rock in this karst landscape, then deposits it as the barriers grow. They keep reshaping the lakes, so the scenery is a process still under way, not a fixed chain of pools.

Kozjak marks the transition from the Upper Lakes, set among less permeable dolomite, to the Lower Lakes in a narrow limestone canyon. That change in bedrock helps explain why the park's lake basins and waterfalls look different as you move through the circuit.