There is a quota on Thalys trains. Those seats can sell out weeks in advance even though regular tickets are still available.
As Sunday is the end of the holidays for a lot of people, I expect trains to be quite busy.
You could take a reservation-free IC to Bruxelles-Midi and from there the Thalys. I'll have a look if there's still seats. Otherwise via Lille. Let me come back to you
You can book it here if seats for pass holder are left. Thalys has only a small amount of seats for Pass Holder.
https://www.b-europe.com/EN/Booking/Pass#TravelWish
booking fee: 4€ on top of the reservation cost.
You need a cover number check it here:
No seats either between Amsterdam and Paris or Brussels and Paris. The solution is now :
- IC Amsterdam Centraal - Antwerpen-Centraal 09:28 - 11:16
- IC Antwerpen-Centraal - Kortrijk 11:37 - 13:01
- IC Kortrijk - Lille-Flandres 13:13 - 13:51
Those trains run hourly so it is only an example above.
From Lille-Flandres or Lille-Europe (10 min walk) dozens of connections for 10 or 20€ (some 1st class fares for 19€ = seat + surcharge for 2nd class pass). Have a look at availability here : https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish
Let us know for questions
Thanks a lot! I was able to book a route as you described.