The Castelli di Cannero are three rocky islets of Lake Maggiore in northern Italy. They are located off the shoreline of Cannero Riviera while administratively forming part of the Commune of Cannobio. They are known as castelli, or castles, in recognition of the ruined ancient fortifications which are found on two of them. All that remains of the castle on the western islet is a ruined tower and some crumbling parts of the wall. The ruins cannot be visited as they are unsafe, but the view of them from the shore or from a boat continues to be compelling.