The coastline of Koh Samui in Thailand is dotted with resorts whose dense tropical grounds spill onto the island's incredible white-sand beaches. Our investigators visited more than 100 of these properties (and took thousands upon thousands of honest photos along the way) to determine the ones that are the most charming, well-designed, and one-of-a-kind. Here are Oyster's top picks for boutique hotels in Koh Samui.