If your destination is Montparnasse, the Air France bus is your best option. Just get on the bus, pay the driver and sit down. There is absolutely no need to book ahead of time.

Kerouac, I checked up google maps and indeed my hotel is 800-900m away from drop-off point of Air France shuttle. Thanks for the advice. I'd walk up to buy the ticket once I land and would buy the round-trip fare as the pick-up as well would be from the same place, making it convenient to lug around my baggage from the hotel.

Kerouac, I checked up google maps and indeed my hotel is 800-900m away from drop-off point of Air France shuttle. Thanks for the advice. I'd walk up to buy the ticket once I land and would buy the round-trip as the pick-up should be from the same place, making it convenient for me to put the luggage in reception area of the hotel after I check-out on my last day in Paris and come back in the evening to just pick it before I leave for the airport.

My browser first showed my response could not be posted hence I re-typed. Only to see both messages are there, neatly next to each other

There is certainly no need to purchase online, but I found it convenient to do so since you can print your ticket and have it in hand when you arrive. There is also a small discount when you purchase on line.

http://www.lescarsairfrance.com/en.html

It's a waste of time, IMO opinion, to purchase a ticket online - just something else to carry across the ocean with you and risk losing. You don't go to any counter when you land - you simply walk outside to the shuttle stop. There's a booth there where you can buy a ticket if you wish, but you can also just get on and pay the driver.

How much is cost of Shuttle? Should i use credit card or pay cash? THX Moe

If there is a discount and I were positive I wanted to take it, I'd do that because it isn't for any one particular bus, I presume. The cost is around 15 euro one way.

Moe, pay however you want, it's up to you.

Each bus destination has a different fare (#2 and #4 are the same) but there is significant cost savings purchasing round trip tickets in advance:

http://www.lescarsairfrance.com/en/tickets-and-prices.html

I would probably take the AF Bus if I were you but the low cost option is the RER B via Denfert Rochereau at 9.25€

I had to go pick up my sister on July 14th from our hotel in the Montparnasse area. I walked to the drop off/pick up place on rue du Commandant Mouchotte. It was a nice, air conditioned bus with comfy seats and a particularly pleasant experience.

I bought the aller retour, which is the return trip fare -- cost about 27 euro; and bought the billet simple (one-way) for my sister when we got on the bus. About 17 euro for her.

I'd say the only difficult part of this is knowing on both ends where you pick up the bus and where it drops you off.

If you're coming out of terminal 2E (most foreign do), after collecting your baggage, you continue on passing through the doors "nothing to declare" or something to declare. From there, there's only one direction to go, and that's straight in front of you past people with signs to locate people and the like, towards a coffee bar, past seats and tables used by people waiting for passengers to pass thru customs.

Directly in front of the coffee bar is a corridor where you can turn left and go down the corridor or turn right and go down the corridor. (You can also go behind the coffee bar to the escalators that go up to the next level).

So what I'm trying to say is that where you come out is shaped like a "T" with the coffee bar right above the "T". OK?

Head LEFT down the corridor at the coffee bar. The first sign you'll see on the RIGHT of you will be "Sortie 8" (on your left you will see the baggage claim behind the windows.

Turn right into "Sortie 8" and just follow the little maze path where there are signs to Les Cars and Paris Disney. You will eventually see on your left the outside driveway and probably one of the buses dropping off passengers. There are 4 places right there where you will see signs that say "Quai". Now each "Quai" is for a particular line of Les Cars -- but of course they aren't Quai 1, 2, 3, and 4 designating that you will go to Quai 4 for Line 4! No, it's more like Quai A, B, C, and D. My recollection is that line 4 (for Montparnasse) is Quai D. If there's a line, go stand there. The guys with the bus will tell you when to put your luggage under the bus in the luggage storage. LISTEN to what they are saying! They will be asking if you're getting off at Gare de Lyon (the first stop) or Gare Montparnasse (the second stop). You need to be able to tell them which one, because the luggage storage has two compartments -- one for each station!

After you get your luggage in the right storage compartment, get on the bus and pay. You can do it in cash or credit card. If you want the return ticket, get the aller retour.

Once you get off at the second stop, remember as best you can where they let you off, because it's on a side street, and all of the streets in that area are NOT on a grid, and there's parts that go under a bridge into a tunnel. So unless you've been there before, you may get turned around!

My suggestion, other than look at a map and try and sort yourself out before-hand is, if you do get turned around, just look up for the Tour Montparnasse and head towards that! From Les Cars at Montparnasse, it's very easy to see.

I don't think you could easily find the Air France bus stop just be going to the tower. You can see the tour from the bus stop, but not vice versa. It's just around the corner from the train station entrance on rue Commandant Mouchotte. It's right across the street from the large Pullman hotel, that's the best landmark, and is actually right in front of the entrance to that new museum of Leclerc/the Liberation/Jean Moulin. At least it's the street entrance, you go up some stairs to the museum there and there are signs for it.

This is a map for the museum (which is actually very interesting) and the stairs to it on that street, it also shows the hotel which is labelled Meridien but it is now Pullman. So the Air France bus stop is right where those stairs are across from the hotel.
http://www.paris.fr/loisirs/musees-expos/memorial-leclerc-et-de-la-liberation-de-paris-musee-jean-moulin/votre-visite/rub_6923_stand_19810_port_15799

Of course if you get dropped off there, you know where it is.

You're absolutely right Christina. From the Montparnasse Tower, you can't see where the bus is located.

My comment in that regard was based on the fact that Rtwin80days planned to take the bus FROM CDG to the Montparnasse stop. I wanted the OP to have a point of reference when getting OFF the bus since landmarks are how I situate myself to an area that may be unfamiliar to me when I need to return.

Had he stated the reverse, as I did when I went to pick up my sister and had to START at Montparnasse bus stop, I would have said scout the area out first or use a good map to find it, as I did.

Sounds like the best option for you -- except if it is raining. I would not like to trudge 800 meters in a driving rain. If it is raining, I would simply hop a cab from the airport directly to my hotel. Cost more, but ---------

Just returned from France. Will write a trip report later. But I wanted to say that we took a cab from CDG to our hotel in the 6th, and then today from Montparnasse train station to CDG. There are two of us. Cost going to hotel was 60 euros including a tip, and the cost going to CDG was 55 euros including a tip. For us, in our 60's, the cab was very convenient and easy.

The Air France shuttle and the Roissy bus are the same thing, right?

No, they are not.

MaineGG, thanks for the link...it gave me a good idea of the options and map.

Sarastro, I want to explore the railway network in Paris definitely. But I guess I'd be too tired after a morning flight (Paris would happen after 2 weeks of Spain trip, so expect some fatigue there). Better to take it easy till I reach the hotel and relax for a while before heading out. I checked out, there are quite a few train stations around my hotel, so should be good to take those.

Surfergirl & Christina, thank you so much for such detailed directions! I am taking notes from this for sure!

nukesafe, I hope it is not raining, else would be a total disaster, which I would end up making fun of, in my trip report

Kwoo, it is just me and instead of 120 euros, I'd be done with 27 euros for the round-trip to the airport. Works well for me, in fag end of my 20's. If I don't rough it out now, when would I?

StCirq, which of the two buses are better? What is your opinion on Roissy?

rtwin, one isn't better than the other. They go to different places, so it depends on where you're headed.