Vathis, Greece offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Vathis, South Aegean, Greece, is known for its picturesque harbor and traditional architecture on the island of Kalymnos. The best time to travel to Vathis, Greece, is from May to September, with average air temperatures around 75°F (24°C) and water temperatures around 73°F (23°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!