The TGV train from Paris to Reims

SNFC is France’s railway. The earlier you buy, the cheaper.
https://en.oui.sncf/en/train-ticket

I didn't have trouble buying tickets on the SNCF website a couple of years ago, but if you run into a problem, loco2.com should be selling tickets at the same price. Do not use RailEurope; it will probably cost you significantly more.

If you are planning to take the train to Reims on the same day your transatlantic flight lands, you might opt to wait until you get through Immigration, because it's hard to predict when flights will land and what the Immigration line will look like.

www.seat61.com is the invaluable guide to all train travel. It discusses another ticket-seller
www.trainline.com

In all cases on major lines, the sooner you buy, the cheaper the ticket. The fast trains require an included seat reservation which means the ticket is valid only on that train. Some changes are permitted on some tickets at extra cost. The SNCF site is pretty clear on these rules and no site will have cheaper prices.
https://en.oui.sncf/en/

I booked through Trainline.com when we did this tour, but have used all the mentioned sights successfully and used seat61 when I had more questions. TGV prices do go up the longer you wait.

Thank you to everyone who replied to my query , its been really helpful ! You are right, the SNCF site is very user friendly and gave me a reasonable price for the TGV tickets. It looks like the TGV trains arrive about 8k from Reims. Has anyone been to that station? If so, do you think it will be a problem to get a cab for 3 people all with suitcases?
Thanks again!

There are two stations in Reims : Reims centre which is best, and Champagne Ardennes TGV, 8km away The booking engine of SNCF lets you choose, normally - try again and see if you can specify. But if you're coming straight from CDG you have no choice, it's the latter. And if it's the latter it's not too big an issue, there are cabs (not sure if you need to prebook, never needed a cab there) and a tram line that can be useful if your accomodation is close to a stop.

Just got back from your tour. You booked your tickets in advance. Hopefully you booked first class so that you have an assigned seats. If you are staying at the same hotel we did, the Grand Hotel Continental, then you will be able to walk with your suitcases to the hotel and there will be no need for a cab. The RS tour office will provide instructions on how to get to your hotel from the train station. It is easy to get to the hotel.

It is a wonderful tour, have a great time!

Hi Ann,
Thanks so much for your reply. We got coach tickets but still have assigned seats. We are staying at the Best Western for our tour, so hopefully that will not be too far. Glad to hear that the tour went well, I am really looking forward to it!

As long as you have assigned seats, that's all that matters! Yes, the tour was lovely and really pretty. Safe travels.

We got coach tickets but still have assigned seats.

That is a slightly confusing statement. Do you mean you got bus tickets? I though you were planning on travelling by train? All seats on a TGV (= High Speed Train) are pre-assigned, same for 1st and 2nd class. The ticket should list train ID (number, date and time), plus coach (vehicle) number and seat numbers.

Yes, we are traveling by train and yes, you are right it seemed that all seats on the TGV are assigned. I like to know where I am sitting. Thanks for your response.

I've used SNCF multiple times without trouble. The main thing is only a few train options pop up for your search. You can ask for more trains earlier or later. Sometimes the train options presented are frequent stop and/or connections and not the best options.

I booked TGV tickets from Paris CDG to Reims on the SNCF website exactly 90 days before our trip and had no problem using my Chase Visa card on-line (although others have had problems as noted in some earlier posts on this Forum; the issue may be whether the card is "Verified by Visa"). We traveled on the TGV on 22 May 2019. It is only about a 30-minute ride (vs. 1.5 hours by car) and cheap if you buy in advance (about 20 Euros per person). Took a taxi from the Champagne-Ardenne Station to our hotel in Reims (cost was 10 Euros). In Reims, we visited the Museum of the Surrender (where Jodl signed the capitulation documents to end the War in Europe in May 1945), the beautiful Reims Cathedral, and did a champagne tasting and cave tour at Taittinger. Walked everywhere that day - about 6 miles.