Lots of ferries coming in and out the port and the entrance is quite narrow, follow the instructions of the pilot guide.
Don't miss: the Aragonese castle (Castello Aragonese). The first part of the Castle, a simple tower, was built in 474 BC by Hiero I of Syracuse, on a rock near the island. In 1441 Alfonso V of Aragon connected the rock to the island with a stone bridge instead of the prior wood bridge, and fortified the walls in order to defend the inhabitants against pirates. The Castle was completed in 1492. The panoramic view of the Bay of Naples is breathtaking. There is a little cafe inside, where you can also have your lunch.