Apart from taking a tour, the easiest way to sget to Pompeii is by train. Its an easy 90 minute trip to Naples from Rome if you take the high speed Eurostar. Then, you take the local commuter train called the Circumvesuviana and get off at Pompeii Scavi. From there, its a short walk to the entrance. The local train is cheap, 4 Euro R/T. For the Eurostar, you must reserve a seat in advance. During busy times, its best to do this in advance as seats do fill up.
Circumvesuviana train system from Napoli. Take the purple line, enter the ruin from Pompeii Scav. station entrance, exit on the other side of the ruin to Pompei station and take the green line back to Napoli.
When thinking about a day trip outside of Rome, Pompeii is a great one. Here's a tip regarding the train when you plan this. Purchase your ticket to Naples at least a day in advance. When you purchase the ticket make sure it is marked "ES". This notes an express train. This will shorten your trip by at least 1 hour. Also you are not required to time stamp your ticket before boarding the train for this trip. One way on the express train is about 2 hrs. The ticket will be a bit more expensive but well worth it in the time you are able to save.
Remember once you reach Naples you will need to catch an additional train, which is not an express, into Pompeii. This portion of your trip will take about 30 min's, so plan to leave early enough to give yourself a full day in Pompeii. You will need it.
You can purchase your return ticket from Naples to Rome if you are committed to leaving at a
prearranged time. Just remember the trains do not wait for you and an "ES" train is not an open ticket.
From Naples or Sorrento take the commuter train to the Pompeii Scavi stop. This is the stop you want to take to see the ruins. From the stop you take a right on the road that runs in front of the station and walk about 1/4 of mile to the entrance.
We found it very easy to get to Pompeii from Naples by train, so it’s not necessary to take a sightseeing tour unless you want to. There’s a great little line called the Circumvesuviana that leaves from an off-shoot of the Centrale railway station in the city. You can buy your tickets at a counter there, or in the main ticket office (where you need to go to the specially indicated counters – 7 & 8 when we were there). We tried both and found the former was quicker so I suggest you head straight to that area of the station.
Trains seemed to be pretty frequent (the longest we waited was about 20 minutes). You reach Pompeii Scavi, the station for the ruins, about 35 minutes out of Naples. Tickets are really good value. We paid €1.70 each way on a weekday (November 2007 prices), and at weekends you can get a €5 pass to cover multiple journeys – great value if you’re planning consecutive days out or want to do as we did and travel to both Herculaneum and Pompeii on the same day.
When you get off the train turn right and you’ll find the main entrance to the ruins just a couple of minutes’ walk along the road. You’ll pass several cafes here if you’re looking for refreshments either before or after your visit – see my Restaurant tip for a recommendation.
The circumvesuviana train takes you pretty to the front gate of Pompeii. For a couple of euros, you can get to Pompeii from either Naples or Sorrento in about a half an hour. Easily the best way to get there.
Once you get to Naples on the train, you must still catch another train to the Pompeii Scavi ruins. This train is the circumvesuviana. It is downstairs in the train station and a roundtrip ticket will cost less than 5 euros. The train leaves every 30 minutes so it is never a long wait for the next one. Once you get on the train, pay attention to the stops. There is a list of the stops by all the doors and an announcement is made at each station. For the Pompeii ruins you want to get out at the Pompeii Scavi stop. This will put you almost at the ticket center to pompeii. In less than 5 minutes you can walk from the train station to the ruins. There is also a small restaurant and shop in the station. I would suggest buying a bottle or two of water as the restaurant inside pompeii, when open, is verrrry expensive.
To get back to the Naples station, you must go down a corridor that leads you under the tracks to the platform on the opposite side. This, too, comes every half hour.
Just take the Circumvesuviana (it's harder to pronounce than to take, or to find) from Sorrento and get off when everyone else does - the stop's called (surprise, surprise!) "Pompeii".
And from the stop, you can take a bus to Mount Vesuvius, which we didn't do.
If you're based in Sorrento (like we were) the best way to travel to Pompei is by Circumvesuviana train. Be sure to buy a ticket and validate it before you board the train! Tickets can be bought in any tobacco shop or at the train stations.
If you take the train, make sure to get off AND ON at Pompei Scavi (Villa dei Misteri). We made the mistake by walking from the archeological site to the new city of Pompei and to try to catch a train from there. We were already on the train to Salerno when we realized that this wasn't the right one ... We got off at the first station, had to take the train back to Pompei, walked from Pompei to Pompei Scavi and finally got on the right train. Woo hoo!
#3: Take the 'real' train to Pompei
Pompeii does have an actual train station, with trains going to Naples, Salerno, and even Rome. It's a bit more expensive but the Circum Vesuviana is a dirty, dirty train. This option offers more comfort and it moves much more quickly. There's even a direct train from Rome to Pompei although the only direct train that we could discover from Pompei to Rome ran on Sundays.
When leaving the train station just walk straight until you hit the piazza. Turn left on Via Plinio and look for the entrance on the right (it's maybe about a 15 minute walk).
#2: Take the Circum Vesuviana to the Pompei: Santuario stop
Actually the stop is just called "Pompei" but Santuario is sometimes used to distinguish it from the other stop. Santuario refers to the large church that dominates the piazza in the modern town of Pompeii. This stop is less common than the other one because the walk to the site is about 15 minutes, but if you're looking to get more out of Pompeii than just the ancient city I would recommend you get off here. I find modern Pompeii fascinating personally. Here is a small bustling town that has grown up alongside the ancient city. Vesuvius is always within sight and looms over the town much as it did 2000 years ago. Residents would always be reminded of its destructive nature when walking past the ancient city. I wonder what they think of it, what does ancient Pompeii mean to them? Why choose to live in such close vicinity to a volcano that will erupt again?
To get to the Santuario stop from Naples, take the Circum Vesuviana to Poggiomarino not to Sorrento. From the train station take the street (Via Plinio) that is directly across from you, walk past the church, go through the piazza and keep walking. The closest entrance will be the ampitheatre gate on the right, however, you can continue to walk straight and walk to the next entrance which is the Porta di Stabia gate, or you can walk even farther and you will come upon the main gate, the Porta Marina entrance.
You can't get to the Santuario stop from Sorrento. You'd have to get off at Torre Annunziata and change trains from there and really that is just too much of a hassle. We figured out quite quickly that we'd get to the centre of town much quicker if we walked from the Villa of the Mysteries stop than if we waited to change trains in Torre Annunziata.
There are actually 3 ways to get to Pompeii depending on where you are and how much money you want to spend.
#1: The Circum Vesuviana to the Villa of the Mysteries stop
This is perhaps the most common, the easiest, and cheapest way. If in Naples, take the Circum Vesuviana towards Sorrento and get off at the above-mentioned stop. The site is less than a kilometer from the train station. Tickets shouldn't cost more than 3 Euros.
If you are in Sorrento take the Circum Vesuviana towards Naples (all trains go to Naples from Sorrento) and get off at the above-mentioned stop.