No. 23 Koh Samui, Thailand
Nearly a million people a year visit this 13-mile-wide island. After all, it’s gorgeous, with a jungle-draped interior and long, sandy beaches. And Koh Samui’s top-tier resorts—the Banyan Tree, the W Retreat, and the Four Seasons—rank among the finest in Southeast Asia. Although you don’t have to leave these resorts’ relaxing confines to enjoy the island’s beauty, more ambitious visitors might venture out to discover the killer snorkeling, or even take in a kickboxing match and browse the stalls at a night market.