NMBS stopped selling tickets to Spain recently because they now only sell tickets that can be issued as e-tickets. Apparently, for Spain, they can't do that yet. They say they're looking for a solution but that doesn't help you now.

You can check free places here. However, pass holder seats for the TGV to Barcelona often sell out a week in advance (very few seats are available and there are very few trains) and this Saturday there are no seats left. The first train Lyon-Barcelona with available pass holder seats is on 29 March.

You can also travel via Cerbère/Portbou. You can check the timetable to Cerbère/Portbou via many sources but the rest is only available from Spanish sources (because Spanish railways don't share their complete timetable with the rest of the world). Here is the complete timetable Cerbère/Portbou - Barcelona. The SNCF trains in this PDF are regional trains that start somewhere in France and continue to Portbou; only the MD trains require a 4€ reservation that can be bought at the ticket office in Portbou or from the train conductor if the ticket office is closed.

Reservations for other TGVs are easier to get (also check availability on the Interrail website) and are also available from the NMBS ticket office, without any booking fee (Interrail charges a booking fee of 2€ per seat).

Edit: availability of pass holder seats in domestic TGVs in France should be checked here since the Interrail booking service still does not show 20€ reservations when the 10€ quota is sold out.

Hi!

Thank you so much for your reply! One question though, it doesn’t say that tickets are sold out, just that it needs to be bought ‘in real life’… Otherwise the pop-up says ‘No price results were found for this connection. It is possible that the train is fully booked for pass holders. Please try searching for another connection or find an alternative way to book.’

Or am I looking at the wrong thing? 

Anyways, thank you once again!

Karel 

At the same time it shows the grey "!”:

It looks like 2 messages could be displayed here. Theoretically, there might indeed still be seats left, since we don't know which message gets precedence here: the "too late for sending via post” message or the "No price results” message. For tomorrow, it also looks like this but I highly doubt there's still something available.

What you could try: call SNCF (+33 1 84 94 3635, press #85 for English. Don't choose French, since then you need a French credit card to pay), ask if they still have seats available for Interrail on Saturday and if so, if you can pick the reservation up in Lille (or Lyon) at the ticket office or ticket machine. They're open until 20:00 today or tomorrow from 8:00. As far as I know, SNCF can also only issue this reservation on paper and not as an e-ticket.

For this train only reservation on ticket-paper are accepted, This means, Interrail sends you the reservation via mail (Post.nl), this means you have to book in advance to get it at home. You can book it also (when seats are available at every desk of Deutsche Bahn, SNCF or RENFE (or travel agency that sells tickets of this rail carriers)).

You could also use the reservation free services via Port Bou. Please note, that the trains on the spanish side are only showed on Renfe’s website and not in the Railplanner APP. You have to add manually the trip (mobile pass).