train from Rome airport to Florence

With one notable exception, you will need to change trains at one of Rome’s main stations (ROMA TERMINI or ROMA TIBURTINA).

There are many options throughout the day (several each hour) until late in the evening. Check them here (select the language of your choice by clicking on the desired flag):
www.trenitalia.com

Enter the names of the stations in Italian:
from FIUMICINO AEROPORTO
to FIRENZE SANTA MARIA NOVELLA

Enter date and approximate time you expect to be at the airport station across the terminal 3. Although possible, it is not recommended you purchase tickets ahead of time, especially discounted tickets, because, if your flight is late and you miss the train, your ticket is unusable. I would buy the train ticket on the spot, when you get to the station. Seats don’t sell out, and if they do for a certain train (extremely rare) you can always find a seat on the train immediately following that a few minutes later.

There is one direct (no changes) from the airport to Florence at 1:53-otherwise do as Roberto has posted

When you search the the forum be sure to filter by Type and Date ( or you’ll get all posts 10 yrs and more older)

There is a competitor to Trenitalia on the route from Rome Termini to Florence offering frequent service:

https://www.italotreno.com/en

To use Italo from the airport, you would first take the Leonardo Express from the airport to Rome Termini.

Thanks so much everyone. This has been really helpful. I do have another question(s) How easy is it to get from the Leonardo Express in Termini to the train to florence? Should we buy the second ticket at termini or buy both at the airport?

I simply googled Rome to Florence. Got your answer

Thanks so much everyone. This has been really helpful. I do have another question(s) How easy is it to get from the Leonardo Express in Termini to the train to florence? Should we buy the second ticket at termini or buy both at the airport? BTW, does Tren Italo really stop its Rome to Florence run at 3:57 in the afternoon? Before then, it runs every 3-25 minutes (and the trip is always 2/5 hrs)

I would purchase the whole journey at FCO with Trenitalia

The LE arrives at Termini just look at the board for your track ( binario ) for train to Florence-look for train number as the final destination of the train is probably not Florence

Pretty sure you will find info here about LE and Termini
You might also search on YouTube

https://www.seat61.com/train-travel-in-italy.htm

Trenitalia has an easy to use app
Use it to purchase your tickets if you like rather than kiosk or window at FCO
You can find track numbers there as well

The train from the airport to Termini will certainly arrive at a different platform (track number) from the train you need to board for Florence. It is easy, in the sense that you must alight the LE then walk to the platform where your train to Florence departs from. I would say to give yourself at least 10 minutes between trains because it’s about 5 min walk.

Before you walk to the platform for the train to Florence you must confirm the track number (track=binario in Italian), like you would do for a flight at the airport where you confirm the gate number on the departure displays, because, like with airplane gates, sometimes the scheduled departure tracks may change, especially when there are trains that are delayed and occupy the scheduled departure track.

Note that the departure big tables or the many video displays will show the train number and the last destination of the train, which may not be necessarily FIRENZE SMN. It is likely that the last destination of your train to Florence (Firenze SMN) will be Milano, or Venezia (Venice), or Torino (Turin) or some other city north of Florence, although in a few cases the last destination may indeed be Firenze SMN. It is therefore important that you know at least the train number you will board, if not both the number and the last destination of that train.

BTW, does Tren Italo really stop its Rome to Florence run at 3:57 in the afternoon? Before then, it runs every 3-25 minutes (and the trip is always 2/5 hrs)

No, Italo schedules trains on the route from 05:40 to 20:40. Perhaps you set a filter for time of day, or have it sorted other than chronologically?

The trip is typically 1.5 hours.

The Leonardo Express arrives on tracks 23 or 24. It can be a long walk if your departing train is on one of the single digit tracks. You can find videos on YouTube showing the walk from the train to the terminal.