Why do I need to purchase seat reservations?

The Interrail Pass and seat reservations can be seen as two components that depend on each other to function. The Interrail Pass is your travel ticket that allows you to board the train, while the seat reservation is your seat ticket that guarantees you a seat on the train.

Some train operators require you to have a seat reservation to board their trains. Therefore, it's important to check in advance whether a seat reservation is needed before boarding a train. If a reservation is required and you do not have one, you may be denied boarding or fined.

Additionally, seat reservations can be beneficial even when not mandatory, as they ensure you have a guaranteed seat, particularly on busy routes or during peak travel times.