Siamanna, Italy offers 1 beach perfect for sunbathing, surfing, swimming, and more. Siamanna, Sardinia, Italy, is known for its proximity to the archaeological site of Nuraghe Losa. The best time to travel to Siamanna, Italy, is in late spring (May), when the average air temperature is around 20°C (68°F) and the water temperature is approximately 18°C (64°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!