The coastline of Castelsardo is formed from imposing red trachyte cliffs which every now and then boast a number of different shades, from dark to the lightest of reds. Not many beaches are found here but all of them are extremely beautiful, accentuated by the wild aspect of the landscape. The beach of Punta Li Paddimi, bordered by a brown reef, is a narrow bay covered with multi-coloured pebbles lapped by a limpid crystalline sea with splendid blue and emerald-green reflections. A number of flat rocky outcrops appear here and there on the shore.