Transferring trains in Florence

18 minutes is reasonable. What is the final destination?

Jazz, we're going to be traveling from Naples to Siena next year, with a change in Florence. How much time should we allow?

My destination is Pisa.

For Naples to Siena I would only buy the Naples to Florence in advance.
The Florence to Siena leg is a regional train meaning you can buy it anytime time the price is fixed the seats are first come fi rst serve.
Also there is a bus from Rome and Florence that go to Siena dropping you off on the hill in the old town. The train does not meaning you have to get a taxi or take a series of escalators to reach the old town from the train station.

Florence to Pisa same thing. Just buy the ticket when you get there. That route is served by regional trains.

So there is no need to worry about a connection. The regional trains are frequent and do not come with or require a reserved seat.

It's quite doable. All trains in Florence are on the same level, so you will not have any stairs or escalators to navigate between one train platform or another. Do be near the door of your arriving train several minutes (or more) before arrival and be ready to disembark immediately. You'll follow the crowd down the platform to the main terminal area, then look up, overhead at the electronic screens that will tell you the platform for your next train. All are within 5 minutes walk of each other, except for a couple that are way down at either end, which could take 8-9 minutes walk. Your Pisa train is likely a Regionale train, which does not have assigned seating, so just get on any car and take any seat. Of course, be SURE to validate your Pisa ticket in the GREEN machine posted at the beginning of the track area. You can use any green machine. Your Naples ticket probably will be for one train, a high speed "freccia" train with assigned seating, so it does not need to be machine-validated. I would NOT wait until Florence to purchase your Pisa ticket, though, as the time would be quite tight to try to do that at a ticket kiosk for the first time. You could purchase your Florence-Pisa ticket at a ticket kiosk in Naples. It will be valid for a 4-hour time period, so choose the first time that you are most likely to want to use it. If you miss that train, it will be valid on the next Florence-Pisa train, if it leave within 4 hours of the first.

I don't recall any regional train tickets I've purchased at a kiosk in an Italian train station being pre-validated. No matter what departure time I select, the tickets print with only the date of travel and the starting-ending destinations. I suggest checking your regional tickets carefully for a pre-validated time and using the validation procedure described above if you're not 100% certain it's pre-validated. If it does have a pre-validated time, note that you cannot depart earlier than that time but you can depart up to 4 hours after that time.

Thanks Jazz, for the tips. The bus sounds great; I'll check that one first, then check the train. And if we do the train, we will definitely buy the Naples-Florence leg ahead of time.

jmauldinuu, thanks for your tips, as well.

Not a problem.

BTW - I've ridden the Trenitalia and Italo high-speed train lines over a dozen times and the they've never been more than a minute late. Even the regional lines I've ridden (Florence-Pisa-Lucca & Venice-Padua-Vicenza) weren't more a couple minutes late. My philosophy, if a high-speed train is going to be really late, it's going to be due to a wide-spread network problem (major track problems, weather, industrial actions, etc.) and everything is going to be running behind. No use worrying about it until it happens...

I've been taking trains in Italy since 2003, at least 6 or 7 trains each time in 13 trips there, and have only had one be late.
It was due to a medical emergency on board.
I think that nowadays, the "Trains are always late in Italy" story or rumour is largely untrue.
Others may have different tales to tell though...…?

Occasionally trains are late. If you miss your connection in Florence I wouldn’t worry too much because their are frequent trains going to Pisa. About one every half hour.

Trains are generally on time with only occasional short delays. There was a terrorist attack that set a fire at an electric substation in Florence, which caused major delays this week, but otherwise high speed trains run on time.

If you miss the connection with a Regionale is not a big deal. You just board the next one. There are 56 regional trains a day from Florence to Pisa.

Don’t forget to validate regional tickets before boarding at the date stamp machine.

One note: when we were there last month we made several day trips to Pisa, Montecatini, and Lucca, and in each case the Regionale departed from track 3 or 4 ... located on the far left of the terminal as you face the platforms. Getting to either requires a little longer walk along the concourse - maybe another 3 or 4 minutes. Really no big deal but you might want to be prepared for it. Don't know if it's standard that all of the trains heading along that route depart from those particular tracks but that appeared to be the case for us.
And they all departed on time.

Yes, trains to Pisa/Siena and Lucca/Viareggio usually depart from low number tracks, 1 to 7. Some may leave from track 5/6/7, that are the first tracks in the main group. Tracks 3 and 4 are shorter, so you have to walk along track 5; track 1, 1A and 2 are somewhat hidden past a building between track 2 and 5.