"Mu Ko Ang Thong National Park is a national park in Thailand comprising a group of 42 islands in the Gulf of Thailand. The islands of Ang Thong are part of the Samui archipelago (Mu Ko Samui), which belongs to Surat Thani province, and lie a few kilometres west of the main islands of Koh Samui and Koh Phangan. The national park, established on 12 November 1980, covers around 102 km², of which 18 km² is land. The islands, which rise up to 400 metres out of a sea that averages only 10 metres deep in this area, are made of limestone." WikipediaWe recommend booking via the website www.kohsamui.tours - the best provider of excursions on Koh Samui!