eurorail

You can use the pass on all trains in trains of Italian Rail, Trenitalia. However, there is a surcharge to use the premium trains, Italian Eurostar. You should be able to use it for Florence to Naples. I think Naples to Sorrento is a private line where the pass is not valid.

Assuming you will go back to Rome at the end of your stay in Sorrento, you would only need a three-days-in-two-months pass (Rome-Florence, Florence-Naples, and Naples-Rome). With a railpass you will have to pay €10 for a seat reservation on each high-speed train you take. A railpass will not be good on Circumvesuviana trains from Naples to Sorrento. A single ticket costs around €4.

Be sure to do your homework. A rail pass especially in Italy may not save you any money.

It looks like you have 2 round trips on the high-speeds. Rome to Florence and Florence to Rome. Then, you have Rome to Naples and Naples to Rome. The total regular fares on the Eurstar Alto Velocita trains for these two round trips is 176Euro. All seat reservations are included in the cost of the tickets. The 4 day in 2 month Eurail pass for an adult is 164Euro. Add 40Euro for the seat reservation fees that Italy will charge you to ride these trains (10Euro per train). The total is 204Euro. As Tim suggests, you can get the 3 days in 2 months pass but this adds up to 188Euro. Given that you will pay Raileurope fees for reservations or you will stand in line at the station anyway in Italy to get them, the pass doesn't seem worth it. Plus, you have the option of riding lower class trains and saving quite a few Euros. If you don't mind an extra hour on the train from Rome to Naples, the fare for the Intercity train (IC) is 20.50Euro or 53% less than the ESAV train. Same tracks. More stops. You can do much the same on the Rome/Florence runs but the journey time on the IC train is almost 2 hours longer. Ugggh. Note that the private Circumvesuviana train system from Naples to Sorrento does not accept the Eurail pass. Neither do the bus or ferry systems making the same run. Finally, there are two bus systems that have very nice buses running from Rome to Sorrento. About 3.5hrs. About 16Euro. Talk about savings. The drawback here is that they only run once a day in each direction.

thank you so much for detailed information. It does make sense to buy tkts in Italy.