Tharnsadet means "river of visited by Royals" and it is the place where King Churalongkorn, The Great Rama V came to many times to walk up the wondrous waterfalls and bath in its pools. King Prajadhipok, the Great Rama VII also visited as has the current King Bumipol Aduldej, the Great Rama IX. Tharnsadet has recently been declared a National Park due to its great historical importance and abundant wildlife.

Tharnsadet Beach is small-sized one from Tharnsadet Waterfall through the sea. Beach is white and good enough for swimming.  The waterfall are more like huge stepping stones and can be approached from numerous places either from the magnificent beach of Haad Tarnsadet or on the road into Tharnsadet.  Accessing here is recommended by experienced motorcyclists only or hiring a jeep or a boat.