Sunthonphu, Thailand offers 1 beach perfect for sunbathing, surfing, swimming, and more. Sunthonphu, Ranong, Thailand, is known for its serene beaches and natural hot springs. The best time to travel to Sunthonphu, Thailand, is from November to February, with average air temperatures around 25-30°C (77-86°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!