Our flight will land at Rome F. Airport about 7:30am and we need to buy rail tickets to Siena.
We will need to take the train to the main station in Rome.
There are trains leaving for Florence then Siena every hour at ten minutes after the hour.
Would we be safe purchasing tickets in advance online for the 11:10am train or should we wait to buy in Rome?
Next question, if we buy at the station in Rome, will lines be long or can we purchase tickets at a machine with US credit cards?
I would not buy in advance. Why not buy tickets at the airport train station, then you will be covered from the airport to Siena. You can also download the Trenitalia app and buy tickets with your phone on arrival.
Buy when you arrive at the airport station since you don't know if your flight will be badly delayed. You can buy at ticket window, automatic kiosk, or Trenitalia app. Credit cards are accepted in all circumstances.
Since you are going to Siena, instead of going to Florence then back track to Siena by bus or train, you should consider taking a bus directly from Rome at the Tiburtina bus station, which is next to the Tiburtina train station. The bus ride is only 3 hours and there are multiple departures with any of the following companies:
FLIXBUS
MARINO BUS
ITABUS
There is a long, recent thread on buying tickets ahead of time.
https://community.ricksteves.com/travel-forum/italy/buying-train-tickets-on-day-of-arrival
The bottom line is you can't predict whether your flight will be on time, how long luggage and immigration make take so buying ahead of time means you might miss your train unless you buy one much later in the day and then end up waiting. Between the two companies there are so many trains just wait until you're ready and buy the next one.
Yes you can use your credit card but by far the easiest way is to use the app. You can preload it with your information on the website account and then buying tickets takes a minute or two.
There are two train companies in Italy - the state run Trenitalia and the private run .Italo that only runs fast trains between big cities.
https://www.trenitalia.com/en.html (Use Italian names for cities - Firenze for Florence and Roma for Rome - for best results)
https://www.italotreno.com/en
Fast trains have reserved seating, multiple classes and you can buy tickets ahead of time at a (sometimes significant) discount trading flexibility for price.
Local regionale trains - like Siena - have one price that never changes and can't sell out so there's no reason to buy them until you need them.
Both companies have apps that let you buy and store tickets as well check trains in motion. I recommend getting at least the Trenitalia one if not both.
A great resource for train travel in general is here: https://www.seat61.com/train-travel-in-italy.htm
Have a great trip,
=Tod
Yes, there is a small chance that your flight is significantly delayed and you arrive too late to catch your train. But there is a much larger probability that you will arrive at Termini with a large amount if time to kill - so research the location of Mercato Centrale so you can have a nice breakfast.
You can buy a full fare ticket in advance which is fully changeable if you need to change to a later train. Trenitalia offers an Economy discount ticket which allows you to change your departure time. An advantage of buying in advance is that you have a better choice of seats. In any case download the app and create an account in advance.
Only you can determine your tolerance for risk.
