Two Coasts, Two Opposite Monsoon Seasons
Thailand's southern peninsula splits the monsoon in two. From November to April, the Andaman Sea (Phuket, Krabi, Railay, Koh Phi Phi, Koh Lanta, Koh Lipe) is calm and crystal clear. From May through September, the southwest monsoon brings swells to the Andaman, while the sheltered Lower Gulf (Koh Samui, Koh Phangan, and Koh Tao) enjoys bright summer sun. Check ferry and DNP park fees in our Island Ferry & National Park Calculator.