Ko Samui, Thailand’s second largest island, lies in the Gulf of Thailand off the east coast of the Kra Isthmus. It's known for its palm-fringed beaches, coconut groves and dense, mountainous rainforest, plus luxury resorts and posh spas. The landmark 12m-tall golden Big Buddha statue at Wat Phra Yai Temple is located on a tiny island connected to Ko Samui by a causeway. Koh Samui is the largest island in the Gulf of Thailand, followed by its two smaller "sisters": Koh Phangan and Koh Tao. Diving, snorkeling, swimming, and basking on the picturesque jungle-backed beaches are popular things to do here, as well as boat tours around the sublime seascape of Ang Thong National Marine Park.