Intercity trains in Belgium and the Netherlands don't have reservations. Hop on and sit wherever you want -> as a tip : train ends are always less busy. Most European trains work that way. :)

You could take the slightly faster Eurostar (former Thalys) but the reservation would cost you 27€ for this short journey. Not worth it ! Intercity is the way to go for sure.

There are no Eurostar/Thalys trains in your screenshot (timetable likely not loaded up for January yet). You can't book reservations on their website (because they don't want to). In that case use eurail.com or https://www.b-europe.com/EN/Booking/Pass#TravelWish (Belgian Railways).

General tips : reservations cannot be made through the app, it only redirects you elsewhere. What you need to do on the app is log the train you'd like to take, this can be done at any point prior to boarding.

More info :

https://www.seat61.com/how-to-use-a-eurail-pass.htm

https://www.seat61.com/interrail-and-eurail-reservations.htm

Thanks so much for the tip! I’ll get on the Intercity for that leg.

My other legs are:

Brussels to Luxembourg

Luxembourg to Zurich

Zurich to Zermatt

Zermatt to Milan

I’ll have a read of seat61’s guide now.

Thanks again for the helpful directions!

Sure, have a look at the guide !

Luxembourg - Zurich can easily be done reservation-free (a train every 30 min from Strasbourg so good flexibility) :

- TER Luxembourg - Metz 07:39 - 08:27 (example)

- TER Metz - Strasbourg 08:42 - 10:10

- TER Strasbourg - Basel SBB 10:21 - 11:38 or later

- IC/IR Basel SBB - Zürich HB 12:06 - 13:00

Feel free to stop along the way !

There are 2 daily TGVs between Luxembourg and Strasbourg/Mulhouse (8€ mandatory reservation on eurail.com) if you prefer. The high-speed leg is quite short but it still saves you an hour. :)

Seat reservations aren't a thing in Switzerland either. Really hop on and sit wherever you want.

Insider tip : some extra 1st class carriages are declassified on busy days (especially weekends) on the Zurich - Visp railway. This means that you can travel comfortably on 1st class seats with a 2nd class ticket/pass ! These carriages are always found at either end of the train, there will be 2nd class paper signs on the doors. Check the train composition on the day on SBB app (should be carriages 18-20).

Visp/Brig - Milan EC trains have mandatory reservations : 13€. This is best done through the Austrian railway company ÖBB (don't ask me why). You've got plenty of time to book but do not leave it to the last minute, these trains always leave full !

There are slower reservation-free alternatives by taking any train to Domodossola (border point) and then a regional train to Milan.

Feel free to ask further questions. Happy to help !