The island's beauty lies within the Mu Ko Petra National Park, where you can find a charming bay known as Crab Bay. This bay features a small, refreshing stream cascading down as a waterfall. Crab Bay is known for its calm waters free from waves throughout the year, especially during low tide when the coral reefs and marine life reveal their splendor along the shoreline. Moreover, the standout feature of Koh Yai is its natural sculptures, consisting of limestone peaks approximately 450 million years old, resembling a castle that juts gracefully into the sea. During low tide, visitors can kayak beneath this magnificent rock formation. Nearby Koh Yai, there is also a fish breeding center run by the Satun Provincial Fisheries, which is a popular attraction for tourists looking to explore the area.