Ile Sainte Marguerite
To visit Ile Sainte Marguerite take the ferry from the harbor at Cannes right of the Palais de Festival (there’s also a large parking). The boat trip takes about 15 minutes to Ile Sainte Marguerite. On the island there are beautiful walking trails (about 10 km to walk around whole island, but you can make it as long as you want) and two restaurants. It makes sense to book the boat online, this saves approximately EUR 1.50. Tickets purchased at the port is EUR 13.50 per person round trip for adults. Children receive discount. On http://www.trans-cote-azur.co.uk/cannes-ile-sainte-marguerite.php you can book online.
From the ferry to the Ile Sainte Marguerite you get magnificent views of Cannes and the luxury hotels like the Martinez, Carlton, Majestic Barriere, Miramar but also on the Esterel mountains and the Palais des Festivals.
For lunch at the island you can visit La Guerite or at L’Escale. Restaurant La Guerite is very expensive but the views overlooking Cannes are fantastic. In winter there is not much open on the island and the ferry sails less often.