Ko Lanta Yai, Thailand offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Ko Lanta Yai is known for Mu Ko Lanta National Park and Klong Dao Beach. The best time to travel to Ko Lanta Yai, Thailand, is from November to April, with average air temperatures around 28-32°C (82-90°F) and water temperatures around 28°C (82°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!