Naples to Sorrento

The Circumvesuviana train works just fine and the fare is about 4Eu. The journey takes about an hours. Yes the train gets crowded but it is the local. I don't think there is bus service from the Naples train Centrale train station. There is bus service and private car service from the airport, however. The hydrofoil is great. The hydrofoil dock is a bit more than a mile from the Naples train station. You can walk it or take a city bus. Also, I don't think that the hydrofoils operate all year round. You don't indicate when you are going.

If money is no object, car service. It's the only one that'll take you door-to-door.

I would take the local train for the 4 euro rather than car service.

The ferry services between Naples and Sorrento operate (weather and sea conditions permitting) all year round. http://www.alilauro.it/orari.php?id_tratta=9:10&lingua=english&cartella= Check nearer your date of travel for an up to date timetable. PS - I would (and do) use a car service but these days we like to travel door to door in comfort! And depending on where you are staying in Sorrento, you may have to use a taxi when you get there and their prices are horrible. Target price for a transfer service is about 70 - 80 euro depending on time of day/year.

We had rented a car so the drive from Naples to Sorrento is not difficult either. Very beautiful drive once you actually hit the coastline. I'm jealous, have a nice trip.

If you are staying ion Naples then hydrofoil/Ferry is best.