Ang Thong National Marine Park 

Ang Thong National Marine Park is a wonderful park at the shore of the Surat Thani Province. It is located to the north west of Koh Samui. This archipelago of around 40 small islands combines hidden lagoons, sheer limestone cliffs, white sand beaches and dense vegetation. The park encompasses 18 sq of islands, plus 84 sq km of marine environments. The Ang Thong National Marine Park was established in the year 1980. Most visitors come on day trips from Koh Samui to relax on the white sands, sea canoe around island's jagged coastlines, explore the lush forests and limestone caves and snorkel among the colorful fan corals. Among attractions is the abundant wildlife, both on sea and in the land. From Koh Samui a couple of tour operators run day trips to the park. Tours depart daily in the high season, less frequently in the rainy season. At least once a month there's an overnight tour. Koh Mae Koh or Mother Island is a must to visit. There is a swimming beach as well as the stunning Thale Noi, a wide turquoise lake bordered by sheer cliffs. This is the golden basin that gives the islands their name.