Traveling the 165 miles (266 km) from Rome to the port city of Salerno southeast of Naples offers great opportunities to see some of Southern Italy's major sites along the way. Traveling on a direct high-speed train will be your fastest choice—the quickest route is under three hours—but if you opt to rent a car or hire a private driver, you can make interesting detours like the archeological ruins at Mt. Vesuvius.
Duration: 2-4 hours
From Roma Termini or Roma Tiburtina, you can catch a train to Salerno about every 30 minutes on either Italo, or the Italian National Railway system, Trenitalia. On Trenitalia, there are frequent direct trains that will take 2 to 3 hours. There are also fast trains that transfer in Napoli Centrale, giving you a chance to take a detour to see Naples. Italo only runs direct trains but they are a bit less frequent than Trenitalia. Departures are from early morning until about 10 pm with both companies.
By Rental Car or Private Transfer
Duration: 3 hours, more with stops
From Rome, you'll have several rental car companies to choose from, particularly concentrated around Roma Termini and Roma Tiburtina stations. It is possible to rent an automatic transmission car in Italy, however, manuals are more prevalent and will be less expensive to rent. You’ll also want to factor in the cost of gas (prices are by liters, not gallons) for your road trip up Italy.
Having wheels will give you a chance to see Southern Italy as you make your way to Salerno, as you travel from Lazio to Campania. Driving inland on the A1/E45 autostrada, you might stop in the city of Naples, the birthplace of pizza, or at the archaeological sights of Vesuvius, or Pompeii, before you continue on to Salerno.
You can also consider going with a private driver, that way you'll have the luxury of seeing Italy while you travel south, without having to worry about navigating. Once you arrive in Salerno, you could continue on with your driver to explore the Amalfi Coast.
Duration: 3 hours to 4 hours depending on the company and route
TTI Leonettibus has the fastest buses from Rome to Salerno, departing from either Fiumicino airport terminal 3, or, Roma Tiburtina station, with buses leaving a few times each day. Flixbus also has a route from Rome Tiburtina to Salerno, with buses running about every couple of hours from early morning until about 11 pm.