South China Sea, Vietnam offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Ca Mau is known for the Ca Mau Cape National Park and the U Minh Ha National Park. The best time to travel to the South China Sea in Vietnam is from December to April, with average air temperatures around 24-30°C (75-86°F) and water temperatures around 25-28°C (77-82°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!