Pre-book High-Speed Italian train tickets or is same-day OK too?

The major downside is that prices are more expensive on the day of. The "Base" fare on Trenitalia is the price you pay if you book the day of, while the cheaper, less flexible fares are only available in advance.

There's enough trains that you typically don't have to worry about them selling out. Seats are reserved though, so if the train is very busy you might not get a seat next to your wife.

Just buy the tickets for the entire leg when you get to the Fiumicino Airport station, there are trains to Florence every 30 minutes at most (change at Termini or Tiburtina) and I've never experienced seats selling out between Rome and Florence (I've always purchased on the spot). I know the supereconomy might save you about 30 euro over the full "base" price, but the risk of a flight delay is always there.

Agreed, no reason to buy tickets to Rome and THEN Florence......walk up to the first open machine, put in "Firenze SMN" as your destination, and it will give you all the best options....then you will have all your tickets, no need to do anything else in Termini besides find the next train.....

Be glad that you were smart and bought all your OTHER tickets ahead of time and saved money, buying on the spot upon arrival is easier and allows you to skip either being REALLY bored while waiting for your train in a few hours or being SUPER stressed hoping you can make your train sprinting through the airport/train station......that's where you save on arrival day!

I have even been known to be picky and will wait 20 more min at FCO to get a better (and less train changes) trip to my city Salerno than hopping on the next Leo Express....all of the options are on the screen for you to decide :) and there's even less chance of the business/1st class seats to be sold out too :)

Follow Roberto advice -- it is more accurate than the first comment. The base fare is the same whether bought 60 days in advance or day of travel. It doesn't change. The other two fare classes are Super Economy and Economy. These are discount fares that come with restrictions as to changing and refunding AND are limited in number available per train. Generally they will be sold out days, maybe weeks before departure. And these fare classes are available in either first or second class. We find little advantage to first class, as second class seat is about equal to business class on the airline. Buy all the tickets you need at the train station in the airport.

The discounted fares can be much less, but as others noted, they are not suitable for arrival day of a transatlantic flight. They are non-changeable, non-refundable, and you can't even get on an earlier train that has open seats. This is a case where it's better to pay the Walk-Up fare.

The train from the airport to Termini is not an ordinary train with reserved tickets that sell out. We would call it the Airport Shuttle. You pay for a ticket on the way to the train from your plane. I doubt that seats are guaranteed, but it is very frequent. Nobody sits at FCO waiting for the specific departure they pre-bought on the airport train.

Tim, it has been explained to me that the Leo Express is treated as just an "expensive regionale" so if anyone arrives with a whole buncha people on a plane, they might be standing :)

Our last trip we bought at the FCO station had us even bypassing the Leo and ending up on an IC train to get a freccia from Termini and not having to change in Napoli to get to Salerno, which I appreciated :)

Thank you all, very much. I now understand the plusses and minuses of each option and will definitely be booking same day. The differences in the Base vs Economy fares don't appear stress-worthy.
Ciao!

We have a similar situation in that we will be landing in Milan and taking the Malpensa Express to Milano centrale then catching a high-speed train to Venice. What I did was I booked a flexible ticket on Italo that I can change up to 3 minutes before departure. The only thing that I would be responsible for is the difference in fare if there is one. I'm taking my chances with landing at 7:00 a.m. and being able to catch a 9:30 train to Venice out of Milano Centrale. If I have to, I can rebook on an 11:30 train to Venice. I may not be able to sit with my husband but it also might give him a good opportunity to try out his limited Italian if I'm not around :-)

Don’t book anything ahead of time, not even base fare. Just buy when you arrive.
If you pay full price (base) and then your plane arrives 3 hours after the train has departed you lose the right to be reimbursed even on a base fare ticket. Tickets are not reimbursable after the train has departed. If you ask for reimbursement before the train has departed, you can get reimbursed, but they keep 20% of it, so you get reimbursed only 80%. Just hang on until you walk to the Fiumicino station. You won’t be stuck in Rome. There is a high speed train every 10-20 minutes departing from Termini and going to Florence, well into the late evening.