Ticket gates on Eurostar close 30 min in advance, although they advise to be there in advance 45 min to 1 h for the secutainment procedure in Paris Nord for Eurostar. So you’lld only have maximum 2,5 h to get from CDG to Paris Nord. The RER from CDG to Nord takes about half an hour.

So count that you would only have 2 hours for all the formalities in the airport and to get to Paris Nord. No idea how much time the proces in CDG takes, but if your flight will be delayed you’ll be in trouble.

IMHO, I would stay the night over in Paris and take a Eurostar the next day and save you all the stress.

Check in will close 30 minutes before departure (although they aren’t always strict with this) but I would suggest arriving a bit earlier than that.

 It’s difficult to know how long arrival, passport queues, baggage etc will take, but I think that’s a doable connection. You don’t have loads of extra time, but there is some slack for delays. 

Two different answers from myself and @BrendanDB !

I would be happy with the connection, but accepting that if the flight is delayed I might be spending an unplanned night in Paris and begging Eurostar for a free change. 

If you want more certainty, plan the night in Paris.

What could also be a possibility is to take a TGV from CDG to Lille, accomodation will be cheaper there, and you can take a Eurostar from Lille to London from there the next morning.

Eurostars can sell out weeks in advance, so I would keep more buffer anyway in order to avoid rebooking. It might not be possible to book you on the earliest available train, in case of trouble.

When are you planning to arrive? Note that it rains strikes and protests in France last months, because of the planned pension reforms, that could thwart your plans as well.

Many thanks for all the responses…

I will be arriving at CDG on Monday,3rd April. 

I suppose ataying at Lille is also a good option cause any delay at the airport will derail the Eurostar booking and I suppose a flight delay will not be accepted by Eurostar to allow an exchange ticket the next morning?

By the way, I will be activating my Global Pass on the 3rd April itself. Can I still reserve a Eurostar seat even when the Global Eurail Pass is not activated yet? I know it's a real rookie question... and should have been answered in the FAQs somewhere…

Thanks again folks.. you guys are great!

You don't need an active pass to make reservations. As you will be travelling during Easter week I hope you are not too late to make a reservation for the Eurostar. 

There is a limited number of pass holder seats on the Eurostar between London and mainland Europe. On popular departures and during high season those sell out weeks, and sometimes months in advance.

The best place to see the availability of passholder seats and make reservations on the Eurostar is 

https://www.b-europe.com/EN/Booking/Pass#TravelWish

If you don't get any result, press "later trains" and eventually you will find the next available connection. 

If you have a mobile pass you need to generate a Pass Cover Number in order to make the reservation at b-europe. You do that here in the PCN generator:

https://community.eurail.com/news-and-announcements-39/pass-cover-number-generator-is-live-5653

That's quite soon, check availability on the 4th of April both from Lille and Paris, as Easter yields busy international long distance via @AnnaB 's links. Then choose accommodation accordingly. 

For ordinary domestic tgv's you can book reservations here: https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

And keep you well informed about possible strikes too, as the social situation in France is very sour at the moment and I don't see it dissolve in the next weeks. 

Thanks for the clarification on Eurostar seat reservation prior to Eurail Pass activation. So just one Pass Cover Number is sufficient for the entire family?

We are 2 adults and 2 children (aged 6 & 8); do I need to make reservations for all 4 passengers? 

I mean, what I am trying to get at is: Do the kids travel free on Eurostar as with the Global Pass?

Thanks again...

The kids ‘travel’ free as long as the have a pass, but they still have to pay the reservation fees, so yes you’ll need 4 reservations.

I didn’t know you were travelling with kids. In that case, I would be a it more hesitant about the 2113 Eurostar being OK. It’s still possible, but kids make everything slower! And rebooking is more expensive and difficult with four.

It looks like there’s pretty good availability on both days from both cities in second class, a bit less in first class.

So you have a choice of where to spend the night - airport hotel, Paris centre, or taking an evening TGV to Lille. (Or London, of course, if you decide to go for it!)

Yes it is. It is not printed on the reservation so really any pass cover number will do.

Thanks again... I had a feeling that each seat reservation will be payable no matter the age of the traveller. Thanks for the confirmation. 

But what I did find odd was that kids under 12 have a discounted fare when buying regular (without Eurail Pass) tickets but no such discounts on seat reservations on top of the Eurail Pass. Am I missing anything here?

Taking the sage advice of this Eurail community, I have decided to proceed to Lille on the 3rd evening and then taking the morning Eurostar to London.

In addition, i learned that there's a direct TGV from CDG to Lille so that will further simplify the transport I suppose... as compared to going from CDG to Paris Nord and then to Lille.

There is no such discount for pass holder seats.

The reason is that the Eurail pass is your ticket - and your children have already benefitted from a 100% reduction!

The €30 is just the (admittedly large) seat reservation fee.

I suppose the Eurostar seat reservation charges are justified with the high demand and premium service.

Was just checking out the railway strikes scene in France and was wondering what happens if the Eurostar I book from Lille to London on 4th morning gets cancelled due to atrikes? 

I know, I may be sounding pessimistic.. but I have no experience here and am counting on getting sound advice from the Eurail community.

Also, what is the best/fastest train route from CDG to Paris Nord? I could not find a direct train.

Yes, it wasn’t so long ago that you couldn’t use Eurostar at all with a pass, so at least there is an option now. I guess they just weren’t willing to take whatever revenue is on offer from Eurail without imposing the extra fee.

Strikes - Eurostar has been less affected by strikes than the national operators in the UK and France, so disruption is less likely. It pays to check out their travel disruption page, though. It’s very unusual that they would cancel all trains, but possible that you might get switched to a different time.

https://www.eurostar.com/uk-en/travel-info/service-information/eurostar-travel-updates

I thought you’d decided to go straight to Lille for your Eurostar the next day? There’s a direct TGV from the airport to Lille at 2107. (There are a couple of earlier ones at 1907 and 1912, but I wouldn’t recommend those, based on your arrival time.)

If you want to go into Paris itself, you need a ticket on the RER (local rail). The pass isn't valid on these trains. It takes 30-40 minutes, and costs €11.45. 

https://parisbytrain.com/charles-de-gaulle-airport-cdg-to-paris-by-train/

Thanks @ralderton,  for the prompt response... will keep checking that page... 

Let me re-phrase that question...  Can it be assumed that Eurostars from Paris Nord to London would have lower chances of getting affected by strikes as compared to Lile-London services... given the fewer trains from Lille? 

Or there can be no such correlation deduced?

No correlation. They will always try to keep some services going to/ from all destinations. So if necessary they might cancel 2 Paris trains and 1 Lille.

But like I said, Eurostar has been much more resilient during the strikes.

Just this weekend my friend was travelling Geneva - Paris - London - Cornwall. Her TGV was cancelled by the French strikes and her UK train was cancelled by the British strikes, but her Eurostar sailed on unaffected! (She had to endure two very long coach journeys though!)

Yes, I am planning on spending the night in Lille and have planned to book on the 2107 as you suggested... but then I was considering the railway strikes situation and was again comparing Lille vs Paris Nord.

Eurostar is a private, international company, with many nationalities. Strikes of the national companies usually don't affect it much. The trains leaving to/from Lille (and Brussels and Amsterdam) are quite often manned with Belgian and Dutch personnel, they don't have any interest in the French pension age discussion, since they don't receive French pensions. (That's why the most strikes are about, last weeks).

Only if the signallers, or security personnel are on strike too, Eurostar get's in trouble. But that's quite rare luckily. 

I would definitely stick to Lille if you have no plans to see Paris. It saves a lot of time. 

If you do find yourself making good progress on arrival at the airport, it's worth finding an SNCF representative at the station, or poking around with the ticket machine. You may be able to swap your reservations onto the earlier TGV.

Eurostar reservations are partially flexible too. If there’s disruption you should be able to swap to a different train (but not route) for free. Even if there’s no disruption, you can reschedule for €15. Both done on the Eurostar website.

After much deleberations finally decided to spend the night in Paris and booked the 0713 Eurostar (9007) for 4th morning. Many thanks for all those who contributed. I am summarizing the links below for anyone following in these footsteps:

@AnnaB 

The best place to see the availability of passholder seats and make reservations on the Eurostar is 

https://www.b-europe.com/EN/Booking/Pass#TravelWish

If you don't get any result, press "later trains" and eventually you will find the next available connection. 

If you have a mobile pass you need to generate a Pass Cover Number in order to make the reservation at b-europe. You do that here in the PCN generator:

https://community.eurail.com/news-and-announcements-39/pass-cover-number-generator-is-live-5653

@BrendanDB 

For ordinary domestic tgv's you can book reservations here: https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

@ralderton 

If you want to go into Paris itself, you need a ticket on the RER (local rail). The pass isn't valid on these trains. It takes 30-40 minutes, and costs €11.45. 

https://parisbytrain.com/charles-de-gaulle-airport-cdg-to-paris-by-train/

Thanks guys… you are awesome!

No problem, you’re welcome. Give us a holler when the mazes and mysteries of the railway network in Europe trouble you again. ;)