Thalys, Eurostar, TGV and 'fixed price' trains
Booking is compulsory in some trains, and is automatically included in your fare. This means that your ticket is only valid for the train and the date you bought it for . Of course, if your option allows this, you can change your booking and take a different train from the one shown on your original ticket.
Tickets for Thalys or TGV can be purchased from 3 months prior to the travelling date (4 months for Eurostar).
Exception: tickets for Thalys Sun and Thalys Snow can be purchased for travelling until the end of the tourist season from the very opening of the sales, i.e. more than 6 months ahead.
ICE and traditional international trains (day & night)
To travel on a traditional international train, you must always have a valid ticket. You can also reserve a seat along with this ticket, but this isn't always obligatory or even possible.
A traditional international ticket can be purchased from 90 days prior to the anticipated travelling date. Your tickets for a single trip are valid for 1 day * from the validity date shown on the ticket and selected by the customer, tickets for a return trip are valid for 2 days in the Benelux and 15 days * in other European countries.
* There are exceptions to these standard validity periods linked to specific fares (e.g. Day returns, Weekend returns etc...) Please always read the specific conditions of your fare carefully.
Breaking your journey
Most travel options also allow passengers to break their journeys as often as they want. But you must not deviate from the scheduled route or exceed your ticket's period of validity.
PLEASE NOTE: if you take trains where booking is recommended or compulsory, you must always make sure you have the necessary reservations.
Your international ticket is only valid for the class shown on the ticket. However, you can upgrade on most international tickets by paying the price difference.
International passes are also a kind of international ticket. They have their own conditions of use, validity, etc.