Chaviolas is an island in Lake Sils, located in the canton of Graubünden. It is the largest islands in Lake Sils, the second largest being located 100 metres west. The island has a maximum length of 120 metres and a maximum width of 55 metres and includes a 40 metre large triangular bay on its northern side. Its highest point is 1,809 metres above sea level or 12 metres above lake level (1,797 m), making it among the highest islands in Switzerland and in the Alps.