Senj, Croatia offers 6 beaches perfect for sunbathing, surfing, swimming, and more. Senj is known for the Nehaj Fortress and its historical significance in Lika Senj, Croatia. The best time to travel to Senj, Croatia, is from June to September, when the average air temperature is around 25°C (77°F) and the sea 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!