Ko Nui, Nakhon Si Thammarat

Ko Nui stands as one of southern Thailand’s most pristine uninhabited islands, floating just off the coast of Khanom in Nakhon Si Thammarat province. This small limestone karst island features dramatic vertical cliffs rising directly from crystal-clear waters, creating an almost fortress-like appearance that immediately captures visitors’ attention. Unlike the crowded tourist islands further south, Ko Nui remains largely untouched by commercial development, offering an authentic glimpse of Thailand’s natural coastal beauty without the usual crowds of tour boats and vendors.

Crystal-clear waters surrounding the island reveal vibrant coral gardens perfect for snorkeling, where colorful parrotfish and angelfish dart between brain corals and sea fans. The island’s rocky coastline creates several small, sheltered coves with pebbly beaches where visitors can swim and explore. Climbing enthusiasts often tackle the limestone cliffs, while others prefer floating in the calm, turquoise waters that remain warm year-round. The sound of waves lapping against limestone creates a natural soundtrack, while the salty sea breeze carries hints of tropical vegetation from the island’s sparse palm trees and coastal shrubs.

Tranquility defines the Ko Nui experience, with only the occasional longtail boat breaking the peaceful silence. The island’s untouched nature creates an almost meditative atmosphere where visitors can truly disconnect from modern life. Swimming in the clear waters feels refreshing and invigorating, while the dramatic cliff faces provide a sense of natural grandeur that makes even a short visit feel significant and restorative.

Visit during the dry season from December to April for the calmest seas and clearest visibility for snorkeling. Longtail boats from Khanom’s main pier provide the most common transport, with trips typically taking 20-30 minutes depending on sea conditions. Since Ko Nui has no accommodation or facilities, plan for a day trip and bring water, snacks, and sun protection. The free entry and relatively easy access from Khanom make this island an excellent choice for travelers seeking natural beauty without the expense and crowds of more famous destinations.