Transportation from Rome airport(FCO) to Siena

The metro is just for use in Rome and only has two lines which skirt the city. They don't go out to the airport. You'll need to take the train to the termini station, either the express train directly to termini or the regional train and then transfer to the metro to get to the termini. From there you can take the train to Florence and then either the bus or another train to Siena. I'm having problems loading the trenitalia schedule page so I don't know if there's a direct train from Rome to Siena. I do believe there's a bus but I'm not sure how long that would take. Donna

I did that trip quite a few years ago. Leonardo Express from airport to Termini.From Termini, train to Chiusi, connect to local train to Siena.You can buy the tickets for the whole trip at Termini. I missed the connection & the trip took longer. Also the train station is a ways from city center. Have since learned there is a bus between Rome and Siena. This is a 3hour, non-stop trip. In Siena the bus stops at either the train station or the center of the city. In Rome the bus stops at the Tiburtina train station, a bit outside of the center, but convenient for connecting to the airport.
For fares and schedules for buses between Rome and Siena (and some other major Italian cities): www.sena.it

We did a similar trip in 2009. We took the train to Tiburtina and took the bus to Siena. The bus leaves you right in town and you can probably walk to your hotel (assuming you're staying in the old town) whereas if you take the train to Siena you will need to take a bus or taxi to the old town. The Rome bus station is in a parking lot across the street and about 1/2 block down from Tiburtina. We bought our bus tickets online and they were less money but it took less time to get there and we waited about two hours for the bus. It gave us time to have our first Italian breakfast! Here's the website for the bus if you would like to check it out. http://www.sena.it/Home/78-1-en.html