Half-moon-shaped Giannutri is the southernmost of the Tuscan islands and easily visited as a day trip from Porto Santo Stefano or Isola del Giglio, from which it is roughly equidistant (about 15km/9 miles). Its 260 hectares (642 acres) consist of an almost wholly unspoiled interior, and rocky cliffs with interesting coves and grottoes. The gorgeous sea and a coastline that drops off to reveal dramatic underwater scapes (including some cool shipwrecks) make Giannutri an especially popular destination for divers. In summer, the wide natural harbor formed by the island's curved shape is freckled with boats big and small, most visiting from other islands in the archipelago. Although Giannutri is 100% parkland of the Parco Nazionale Arcipelago Toscano, much of the island is privately owned and, in summer, it's taken over by an exclusive colony of wealthy wannabe Robinson Crusoes from the Italian mainland.
The island is a mass of jagged calcareous limestone, made less harsh by a thick blanket of macchia mediterranea. On walks through the interior, you'll inhale the aromas of wildflowers and herbs that grow rampant. On the northwest part of Giannutri, there are significant ruins of a Roman villa; dating from the 1st to 2nd centuries A.D., it most likely belonged to the prominent family of the Domitii Ahenobarbi, of which emperor Nero was a very notorious progeny.
There are no hotels or campsites on Giannutri, just a very small number of vacation-rental apartments and villas that need to be booked well in advance. Giannutri has two restaurants and a grocery store, but it's a good idea to bring your own essential provisions like water and sunscreen.