Train ticket reservations - cost savings?

You can save a lot by buying early. Some tickets are not discounted at all but the high speed trains offer great discounts when purchased early. For Rome to Naples you can get the super economy fare of 19 euros versus the base fare of 43 euros. Same with Rome to Florence. From Florence to Venice you can pay 19 for the super economy or 45 for the base fare. Once the super economy tickets run out they are gone so if you wait you'll pay more. On the day of travel you'll pay the base fare.

Donna

You have three levels of fares in Italy for all trains requiring a reservation. Super Economy, Economy, and Base. The SE and Econ tickets come with restrictions and limited quantity. Probably more SE available on the 6am train than on the noon train. Once the limited quantity is sold, that is it. Buying at 120 days will insure the most availability. At 60 days, who knows? All could be gone or some might still be available on limited trains. The SE offer significant discount, Econ less so, and, of course, Base is the standard fare.

One exception of all of the above. The Regionale trains are open seating - no reservation. Get on and go. If you cannot find a seat you stand till one becomes available - general not a major problem. Regionale trains are one price, never discount, and cheapest but also the slowest since they make lots of stops. Since your trip will involve various trains from Regionale to high speed (Florence to Venice, for example) and IF you are willing to lock into a fixed schedule, then buy the high speeds trains now to take a advantage of the discounts. These tickets will be non-refundable and non-changeable. For the R trains, buy the tickets at the station. You can only buy R tickets seven days in advance on line so that probably is not an option for you. However, never buy an R ticket on line.

great,

Regarding the routes you'll be travelling.....

• Pompeii to Rome - The first leg will be via Circumvesuviana so no discounts are possible and can't be purchased online AFAIK. Just buy your ticket at the local station. The second leg from Napoli Centrale to Roma Termini will likely be via high speed Freccia train, and that can be purchased online. Note that the ticket will be specific to train, date and departure time and can ONLY be used on the one train listed on the ticket.* If you miss that train for any reason and have one of the cheaper tickets, it will be worthless and you'll have to buy another at full (Base) fare.
• Rome to Cinque Terre - there are a variety of trains used on that route, so whether to pre-purchase will depend on which train you plan on using. I'd suggest using one of the direct trains to La Spezia Centrale, and there's a departure you could take at 09:57, arriving 13:58. That's an InterCity train so you could pre-purchase. However the trip from La Spezia to whichever of the towns you're staying in will likely be via Regionale, so the ticket for that is best purchased locally. You can buy that from a Kiosk or ticket office at Roma Termini the day prior to travel, but be sure to validate it before boarding the train on the day of travel or you'll risk hefty fines which will be collected on the spot!
• Cinque Terre to Pisa and then to Florence - Again, there's a variety of trains used on that route. You'll need to check the Trenitalia or Bahn.de websites to determine which departure you want to use, and the specific composition of the trains. If any legs of the trip will be via Freccia or InterCity, you can pre-purchase tickets. If any will be via Regionale, buy the tickets locally, but DON'T forget to validate prior to boarding on the day of travel.
• Florence to Venice - That trip will almost certainly be via Freccia high speed, so you can pre-purchase. Again, the ticket will be specific to train, date and departure time, so be sure not to miss the train! On that route, you could also use the competing Italo Treno service (your choice).

It's improbable to give a ballpark savings amount since the time it takes to sell out of a super-economy or economy ticket varies - for peak season travel on popular routes, the lowest fares can be sold out within days. I've gotten a super-economy fare at the ticket window off-season on a less popular route.

As more people learn about buying tickets in advance, the quicker those super-economy fares will disappear.

There is also a mid-range Economy fare of about €29, in between the high and low rates that Donna detailed in the first reply. Those rates are all for second class. Faster trains in Italy now have several classes and the next "upgrade" level typically costs €10-15 more for these distances.

It is not that they are cheaper bought early, it is that the cheap tickets are bought up early. It is possible you would not be able to get them 119 days out if by some chance large numbers of people bought them on the 120th day. There are a limited number of the cheaper tickets and they get sold out when they are sold out not according to a particular time table.

It is not that they are cheaper bought early, it is that the cheap tickets are bought up early. It is possible you would not be able to get them 119 days out if by some chance large numbers of people bought them on the 120th day. There are a limited number of the cheaper tickets and they get sold out when they are sold out not according to a particular time table.