Navigo Decouverte

No.

Get them at the airport RER station if you plan to use them to get into Paris. Come prepared with your head shots 25/30mm.

Yes, you can! If you have the app on your phone. We have the Ile de France Mobilites app on our Android phones and always buy our weekly passes before we arrive. I believe they start selling them the Thursday before that week?

Good to know. I have read that the pass can only be downloaded once in France. But I always use the card and not the phone app so if you have done it, I guess that information is wrong. I find the card more secure than having to fuss with a phone every time I have to go through a turnstile but lots of people like having their travel passes on their phone.

The Navigo Découverte is a card (5€) and may only be purchased in the Ile de France.

The Navigo weekly pass may be loaded electronically onto any smartphone configured with either the IDF Mobilités app or the Bonjour RATP app.

I'm trying to set up an account on the Mobilites app, and it's saying I have to have a french phone number in order to set it up; do you have a phone number with the +33 prefix or did you get around this somehow?

As usual thanks so much for info. I think I will just relax until we get to CDG!!

In response to: "it's saying I have to have a french phone number in order to set it up; do you have a phone number with the +33 prefix or did you get around this somehow?"
just type in your international-format number with the prefix after the +
I successfully did this with my UK number :=)

I believe you can buy a Navigo EASY pass in advance, but not a Navigo Decouverte.
The ND needs a photo stuck inside the holder so it has to be done when you arrive.

The Navigo Easy and the Navigo Découverte are cards. They are only sold in the Ile de France region. You might be able to purchase an Easy card on the Eurostar. The Easy card holds only tickets and day passes. The Découverte card only holds passes (day/week/month), is nontransferable, and requires the bearer's name and photo. The photo must be a clear likeness of the bearer. Attaching a blurry photo can result in a fine.

You can setup any smartphone as a card substitute by installing and configuring either the Bonjour RATP app or the Ile de France Mobiltiés app. This can be done anywhere but some have trouble configuring the app when they are not in France.

Each user requires his own card or app, no sharing.