|Buying Train Tickets at CDG Airport|
Except for private transfer, which you book online before you arrive, you may need cash euros to pay for your ride to the city center. There are currency-exchange booths located prominently in the Arrivals and Baggage Claim areas, but ATMs (cash machines) are usually the thriftier option, with a better rate of exchange. ATMs are not as prominent, so you may have to search for one, but you may save money.
Ask or look for un distributeur de billets.
There's one in Terminal 2E (Air France, Delta, SkyTeam) outside baggage claim near the Information booth, and another at the bank branch on Level 4 of Aérogare 2, the airport's main train station.
Find Aérogare 2
From anywhere in the airport, follow signs reading Transports (Ground Transport), RER Trains, or Paris par train (Paris by Train). You will end up at Aérogare 2 (Train Station 2), CDG Airport's main SNCF and RER train station.
Purchase Ticket(s) or Transit Pass
You may wait in line at the ticket office and buy your ticket with cash euros or a debit or credit card, or you may buy your ticket from a ticket machine. You cannot buy a ticket on the train. You must have a ticket to access the train station and to exit the station at your destination.
Somw Navigo transit passes are valid for unlimited travel anywhere in the Île-de-France (Paris region), including between Aéroport Charles de Gaulle and central Paris. It may make sense for you to purchase a Navigo pass right at the airport and use it to travel into Paris—but you'll need a few items to do so. More...
Enter the ticket office marked:
(See the photo on the right—>).
(Do not enter the office marked "TGV - Billets Grandes Lignes - Mainlines Tickets - Billetes Grande Líneas." That office is for TGV intercity train tickets, not tickets to Paris.)
Wait in line and, if you're not going to buy a Navigo transit pass, ask for a ticket to Paris (un billet á Paris). The ticket agent will sell you a one-way/single ticket or round-trip/return ticket good for the RER Line B train all the way to central Paris. The ticket is also valid to continue your journey by Métro once you arrive in central Paris, so be sure to keep it!
The machines offer instructions in various languages, including English.
Check the instructions to assure the machine will accept the sort of payment you intend to provide.
A "smart" credit card with a computer chip (puce) and a PIN (Personal Identification Number) may work to buy your ticket. (Most "smart" credit cards issued in the USA work on the chip-and-signature system, so you must request a PIN from your bank or credit card company. More...)
If you don't have euros nor a "smart" credit/debit card, find a distributeur de billets (ATM/cash machine) and use your home bank card to withdraw some euro notes. There are several near the ticketing machines and one on Level 4 of Aérogare 2 at the bank branch. If this doesn't work, find an airport Bureau de Change (currency exchange office) and change some cash to euros.
In Aérogare 2, look for signs reading vers Paris (To Paris), RER B, and voies 11 & 12 (tracks 11 & 12). Follow the signs to the turnstiles. Here's the route you'll take (map).
Keep Your Ticket!
On the RER system, you must insert your ticket into the turnstile both to enter and to EXIT the system!
When you enter, insert your ticket, then take it from the pop-up slot atop the turnstile and keep it with you.
At the end of your train journey, insert it into the turnstile to exit the RER system.
Pass through the turnstile and descend to tracks 11 & 12.
All trains from tracks 11 & 12 go to central Paris! But some trains are faster than others. Here's how to choose a fast train for the ride into Paris, here are more tips on riding the RER trains, and here's an important warning about taking the RER B train back from central Paris to CDG Airport. More...
Your destination is probably one of the five RER Line B stations in central Paris: Gare du Nord, Châtelet Les Halles, St-Michel Notre Dame, Luxembourg or Denfert Rochereau. (You can get to Aéroport d'Orly from the RER B Denfert Rochereau or Antony stations. More...)