For diving enthusiasts, the underwater environment here can be a real discovery. Just for starters, marine biologists chose St. Andrea to study the seaweed called "Posidonia". This marine plant with long, thin green leaves, which reproduces through pollination, is a rare find in the Upper Tyrrhenian Sea and is proof of just how uncontaminated these waters are. In Spring, the seaweed bears fruit similar to small olives (in fact they are called "sea olives"). The "fields" of Posidonia are the ideal habitat for many fish species which are abundant here: schools of small, brightly coloured fish swim through the vivid green Posidonia, along with sea perch, two-banded bream, salp, and other local varieties. Along the seabed, starfish and the "noble fin" clams show their colours. For more expert divers, there are many interesting dives near the off-shore rocks called "le Formiche della Zanca", in the vicinity of Cape St. Andrea. Descending along the seaward side, at a depth of about 40 mt., gorgonia show off their bright colours. It is also easy to come across lobster, eels, and large dentex. And with a bit of luck, you might even see a sunfish in summer.
Let's not forget that off St. Andrea's shores, two wrecks of Roman merchant ships have been found. The first is just off the coast at a depth of only 10 mt., while the second lies 193 mt. from shore at a depth of 45 - 47 mt. The former was carrying grindstones for wheat; the latter held amphorae full of wine from the southern Campania region. Many of the finds from the two wrecks are exhibited in the archaeology museums of Marciana and Portoferraio. But the true, natural museum which preserves the two ships and part of their load is still the sea floor, despite the numerous raids of treasure "predators" in the past.

An underwater paradise
The various activities offered by the Hotel Ilio include snorkelling and diving, discovering the submarine world of Capo S. Andrea, in Elba