Sardinia has the best beaches in the Mediterranean. The must visit list includes the beaches of the entire Costa Smeralda, Cala Gonone and Li Coggia, although it is La Pelosa (near the town of Stintino) that rates as the most amazing beach of them all.
If mysterious and private coves are your ideal, the Golfo di Orosei's many cliffs and concealed spots are your best bet, and the different islands of La Maddalena can also provide a lot of privacy. The Costa Verde and Costa del Sud's safe and smooth waters are also appealing at any time of year. Finally, the Isola dei Gabbiani (though not on mainland Sardinia) is a treat with its kite surfing, scenery, and options for hiking so close by.