Neptun, Romania offers 5 beaches perfect for sunbathing, surfing, swimming, and more. Neptun, Constanta, Romania, is known for its beautiful Black Sea beaches and the Comorova Forest. The best time to travel to Neptun, Romania, is from June to August, when the average air temperature is around 25°C (77°F) and the water temperature is approximately 23°C (73°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!