Home Napabele Lake Napabale Lake is at the foot of a hill, connected to the sea via a natural tunnel. At low tide swimmers can traverse this span of water for a most unusual experience.
However it is considered unadvisable and dangerous to attempt this feat during high tide, as the water rises to only one half meter from the roof of the tunnel.
Motonunu Lake is known for its clean, clear, dark blue water. Through it is also connected to the sea, its water remains fresh and not salty. Both lakes are 15 km from Raha, the capital of Muna Regency, on Muna Island. They are accessible by sailboat, from Raha, in only 45 minutes.
Quoted from :http://www.indonesia-tourism.com/south-east-sulawesi/napabele_lake.html