Denizkoskler, Turkey offers 1 beach perfect for sunbathing, surfing, swimming, and more. Denizkoskler, Istanbul, Turkey, is known for its proximity to the historic Bosphorus Strait and its scenic waterfront views. The best time to travel to Denizkoskler, Turkey, is from May to September, with average air temperatures around 25-30°C (77-86°F) and water temperatures around 22-26°C (72-79°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!