Fodor's Expert Review Mu Koh Angthong National Marine Park

This archipelago of 42 islands covers some 102 square km (40 square miles) and lies 35 km (22 miles) northwest of Koh Samui. It's around 45 minutes there by speedboat from Koh Samui. The seven main islands are Wua Talap Island (which houses the national park's headquarters), Phaluai Island, Mae Koh Island, Sam Sao Island, Hin Dap Island, Nai Phut Island, and Phai Luak Island. The islands contain limestone mountains, strangely shaped caves, emerald-green lakes and ponds. Most tourists visit on a one-day trip, which can be arranged from Koh Samui. Numerous operators offer trips. Recommended outfits include Samui Explorer. Prices vary depending on the tour (some offer kayaking around several islands, and others take you out on small speedboats for snorkeling or cave tours). The park is open year-round, although the seas can be rough and the water less clear during the monsoon season, between October and December.