Kastriani, Greece offers 1 beach perfect for sunbathing, surfing, swimming, and more. Kastriani, South Aegean, Greece, is known for the Kastriani Monastery, a significant religious site with stunning views of the Aegean Sea. The best time to travel to Kastriani, Greece, is from May to September, with average air temperatures around 75-85°F (24-29°C) and water temperatures ranging from 70-78°F (21-26°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!