Underrated Islands in Thailand 2026: Beyond Phuket, Samui, and Phi Phi

Thailand's island fame rests on a handful of heavily marketed destinations — Phuket, Koh Samui, Koh Phi Phi, Koh Tao. But in a country with 1,400+ islands, extraordinary alternatives exist for those willing to look slightly further. Koh Kood (Koh Ku'd), Gulf of Thailand: consistently rated one of Thailand's most beautiful islands but remains genuinely off the mainstream circuit. No airport, no 7-Eleven, no traffic lights. Turquoise water, jungle waterfalls, and empty beaches. Accessible by ferry from Trat province (3–4 hours). Small but high-quality resort collection, plus budget bungalows for backpackers. Koh Yao Noi, Andaman: a 30-minute speedboat from Phuket but feels like a different country. Predominantly Muslim fishing community, rubber plantations, and one of the Andaman's most atmospheric islands. Cycling the island takes about 4 hours. The view of Phang Nga Bay's limestone karsts from Koh Yao Noi is extraordinary. Stay at Six Senses Yao Noi for luxury or a simple guesthouse for budget. Koh Libong, Trang: Thailand's largest undeveloped Andaman island, famous for dugong (sea cow) sightings — one of Thailand's last significant dugong populations feeds on seagrass beds here. Reached by ferry from Trang's coast. Almost no tourist facilities outside a small eco-resort. Koh Yao Yai, Andaman: Koh Yao Noi's larger sister island; even quieter, with vast beaches and fewer resorts. Good for motorbike exploration. Koh Chang's interior, Trat: despite being Thailand's second-largest island, Koh Chang's interior is almost entirely national park. The west coast resorts are fairly well-known but the east coast is accessible only by motorbike and offers isolated beaches and genuine wilderness. Koh Mak, Trat: next to Koh Kood; flat, mangrove-fringed island with calm beaches and a slow-paced resort scene. Perfect for couples and families seeking total relaxation. No Full Moon Party equivalent. Koh Libong and Koh Sukorn (Trang): two quiet Muslim fishing islands near Trang accessible by ferry. Sukorn in particular has almost no tourist facilities but simple bungalows and an extraordinary slow pace. These islands reward those who prioritise natural beauty, cultural authenticity, and solitude over facilities and nightlife.