I'm not sure what is going on there, but it looks like some trains are not open for booking yet and others might already be full (although that would seem strange so far in advance). You could also call SNCF (press #85 for English) to book and see what they say.

Note that there's always the option to take reservation-free trains via Portbou.

This is the last non-stop leg of for most a much longer trip. The comp. will not want to spoil revenue as there maybe pax who do the whole route. It is in fact a very old (trick you may call) to only book people in the same amount as those who lve train at Narb or do only IPA=if place available on the last day.

And as rian points out-by using local trains=change Port Bou from SNCF TER to rodalies/REFE/broad gauge, its all included-and with local tickets maybe even cheaper as a passday. BUSfares range from 11,99.

That’s correct. I’m travelling from Paris to Barcelona and this would be the last part of the trip. There are 4 daily trains from Narbonne to Barcelona , so it would be very strange to have them all already booked. I’ll try calling or maybe making a reservations once I’m in Paris.

The Port Bou option takes too long. I’m travelling with kids, so I need to get to Barcelona in a shorter trip.

Thanks so much for your help!