Stopover in Brussels on Thalys?

Sounds like it might be expensive, because Thalys trains are pricey to begin with. I think Brussels is worth an overnight. We stopped there en route from Bruges to Paris years ago, and it was very easy to check bags and spend a few hours in the town. We found it very worthwhile and easy to get around. I regretted not having time for the main art museum, which we walked right by. I think you may be able to save quite a lot by booking the Thalys trains in advance, but not sure about that. We purchased the day of travel and it was a very expensive ticket.

Unlike most trains in the Low Countries, Thalys works like an airline- your ticket buys you a specific seat on a specific train. So, unless you purchase your tickets that way, you can't hop off one Thalys train and catch another one later. Without crunching the numbers, it might be cheaper just to ride the normal non-Thalys ICE between Amsterdam and Brussels, and buy the Thalys leg for Brussels to Paris. You'll save by buying the Thalys ticket in advanced, but the ICE costs the same no matter when you buy it.

It makes sense, but it is going to cost you € 20 extra. The cheapest possible Amsterdam-Paris tickets cost € 39. The cheapest possible Amsterdam-Bruxelles ticket (with Thalys) cost € 29, plus another € 35 for the cheapest possible Bruxelles-Paris tickets (total: € 59). Mind you, the normal Benelux trains Amsterdam-Bruxelles takes now 80min longer than Thalys and it costs € 32, so there is not point in not buying an advance, faster Thalys leg for your trip.

Amsterdam-Paris: Standard 2nd class Thalys fare is €130. Booked well in advance (up to 90 days allowed) at thalys.com, the cheapest Smoove fare is €35. Amsterdam-Brussels: Standard 2nd class Thalys fare is €69. The cheapest Smoove fare is €29. Brussels-Paris: Standard 2nd class Thalys fare is €90. The cheapest Smoove fare is €25.

Thanks for the replies, I appreciate the info.