Lake Ranau is a crater lake in the extinct caldera of Mount Seminung. At 16kms wide and nine kilometers wide, it's impressively large and boasts crystal clear water. Tourism here is still in its infancy, but there are plenty of amenities and activities to make any visitor comfortable.
Excursions can be made to small islands within the lake, waterfalls, and hot springs. Coffee plantations, rice fields, and banana forests fill the land around the lake. Subik waterfall is a pleasant 15-minute walk from the main village, while more dedicated hikers can trek to the summit of Mount Seminung.
A boat trip on the lake is a must-do. There are two small islands in the middle, and plenty of boatmen to take you out there. Marisa Island has some hot springs, while Puyang Seranjangan has a modest resort where you can stay overnight. There is even an elephant center on the shore of Lake Ranau that takes visitors trekking on the back on elephants.