Ordinary train tickets between Belgium and the Netherlands require a travel date. An “open ticket” lets you choose your departure time on the date printed on the ticket; it does not let you travel on any date you like. [SNCB International explains the distinction.](https://www.b-europe.com/EN/Questions/Tickets)

For international journeys, the rules depend on the service:

- On EuroCity and Eurocity Direct, a Flex ticket lets you choose a departure on the specified date, route and train type. A cheaper Saver ticket is valid for a particular train and date. [SNCB’s ticket conditions](https://static.b-europe.com/EN/Trains/EuroCity)
- Eurostar tickets are valid for a specific departure and date. [NS International’s validity guide](https://support-en.nsinternational.com/app/answers/detail/a_id/8609/~/how-long-is-my-ticket-valid-for)
- SNCB ticket machines sell cross-border tickets to Maastricht and Roosendaal. These tickets still require a travel date. [SNCB sales channels](https://www.belgiantrain.be/en/support/customer-service/sales-channels/)

For journeys within Belgium, ordinary tickets also have a specified date. You can generally choose a domestic train on the ticketed route that day, subject to any off-peak restrictions. Advice recommending an undated Rail Pass or Standard Multi is outdated: SNCB withdrew those products on 15 October 2025. [SNCB ticket flexibility](https://www.b-europe.com/EN/Questions/Tickets), [Standard Multi withdrawal](https://www.belgiantrain.be/en/tickets-and-railcards/railpass?journey=1)

For your friends, I’d prepare the routes and simple instructions now. Once they confirm their travel dates, buy the tickets online and send them the PDFs to print or save. A Flex ticket for the international journey would let them choose their departure time, which may help if they’re nervous about travelling. Use the station names exactly as they appear on the tickets, and give clear instructions for any changes of train.