Thalys: Tips and Tricks for cheap train tickets
In general you have to book early and outside rush hour to find the best deals. Train tickets from Brussels start from € 29 and from Amsterdam from € 35.
If all cheap tickets from are sold out you can still find some great deals if you travel through Lille. First book a regular ticket to Lille (possible through HappyRail), add this to your cart, and than book a ticket Lille to Paris. The travel duration is more, but it can save you half the price you would be for the Thalys.
If you travel from Amsterdam you can try to break the ticket in Brussels. First you book the regional train to Brussels which is not very expensive, you add this ticket to your cart, and after that you search for a connecting train from Brussels. From Brussels there are much more Thalys-departures than from Amsterdam, so you have a better chance of finding a better deal.
Travel first class
It may sound odd, but sometimes first class is cheaper or just a little bit more expensive than second class. This is mostly the case in weekend if there are almost no business travelers on board.
First class has some great advantages over second class: besides more space, you have better Wifi and you get a free meal and acces to the Thalys lounges at Amsterdam Centraal, Brussels South and Paris Gare du Nord.