Than Sadet Waterfall

Than Sadet Waterfall is a multi-tiered cascade on the eastern side of Ko Pha Ngan Island in Surat Thani Province, within Than Sadet-Ko Pha Ngan National Park. Fed by the island's largest watershed, it forms pools and streams flowing to Than Sadet Bay. Notable for royal visits since the reign of King Rama V, whose inscribed initials remain on rocks, it is a scenic natural attraction surrounded by protected forest and accessible via a short trail.

Visitors can expect a forested national park setting with a stepped cascade flowing over large boulders into natural pools that empty toward Than Sadet Bay. A short, uneven trail leads through tropical forest to viewing areas and boulders bearing royal inscriptions. The site is natural and undeveloped, with areas for sightseeing, photography and paddling in pools when water levels permit. Surroundings include dense forest, streams and nearby beach access.

Than Sadet Waterfall has been visited by Thai monarchs since the late 19th century. King Chulalongkorn (Rama V) visited in 1888, 1889, 1892, 1901 and 1909 and carved his initials on rocks, followed by visits from King Prajadhipok (Rama VII) and King Bhumibol Adulyadej (Rama IX). The inscriptions remain preserved as historic markers within the national park.

The waterfall is regarded as a royal and culturally respected site due to its association with the Chakri dynasty. The royal inscriptions are treated with reverence and the area is maintained as part of the national park heritage, reflecting its significance in local history and national commemoration.