Getting into Rome from the Airport
The Leonardo Express is the name of the train that will shuttle you from Rome's main international airport, Fiumicino, to central Rome's Termini train station. A Leonardo Express train leaves every half hour from the airport to the city and from the city to the airport. From my experience this your best transportation option, if you want to save a few euros you could take a bus shuttle.
ARRIVING AT FIUMICINO AIRPORT ROME
Terminal A is for domestic flights, Terminal B is a mix of domestic and international, and Terminal C is where you'll find major international flights.
The Rome airport code is FCO.
After you've picked up your luggage, follow the signs to Stazione FS/Railway Station. You'll have to go up 2 floors to find it.
Buy a ticket "Per Termini" at the FS ticket counter or from one of the machines in the station. A ticket costs 14 Euros. You must validate your ticked by inserting it in the validation machine before you enter the train.
Upon returning to the airport from Termini, you'll find the train on track 24. You can buy a ticket at the Alitalia office at track 22 or from other places and machines in the station.
GENERAL LEONARD EXPRESS SCHEDULE
From Rome Termini Train Station to Airport: Trains to the airport start at 5:52 in the morning, with trains running at 22 and 52 minutes after the hour. The last train of the day to the airport is at 22.52 (10:52pm)
From Rome's Fiumicino International Airport to the Termini Train Station: Trains to Termini Station start at 6:35 in the morning, with trains running at 5 and 35 minutes after the hour. The last train of the day departs at 23.35 (11:37pm)
The distance between the airport and central station is about 37 km, your travel time is just over 30 minutes.
Important Note: These schedules may change, but in general the trains run every thirty minutes.
COST: You can get the cost from the Treniitalia web site. Currently (2014), the price starts at 14 Euro, depending upon where you buy your ticket. You can order tickets on the Leonardo Express online from Rail Europe. The tickets, according to the website, are good for a whole day.
At Rome Airport the train station is well signposted within the passenger terminals, follow the signs to Stazione FS/Railway Station. You'll have to go up 2 floors to find it.. Its a 5-10 minute walk, but you've probably already walked a similar distance from your aircraft to baggage retrieval and customs. The walk is completely covered, and there are moving walkways and escalators/lifts.
Once at the Fiumicino Station there are automatic ticket machines (have some Euro with you, some machines will not read some types of US credit cards), the official ticket desk and three or four other independent outlets that all sell tickets for the Leonardo Express train.
Note : The station has three platforms and other local trains also terminate here. So do check which platform the next Leonardo Express train departs from, even if there is only one train in the station.
At Termini Train Station in Rome, the Leonardo Express is found on track 24, much closer to the main tracks than it was a couple of years ago. Be aware that any offer to help you buy tickets or carry your bags is likely to lead to a demand of money from you.
Where to Buy Tickets at the Rome Termini Train
Tickets can be purchased at the main ticket windows, as well as at the automatic ticket machines and at the news/tobacco stores in the foyer of Termini station.
Be sure you validate your tickets prior to boarding the train by using the yellow or green machines located on the waiting platform of the tracks.