For July you're not late.

Do you have an Interrail pass or do you intend to buy one? Then you already have a ticket and you only need to book a reservation. Paris to Barcelona can be booked on interrail.eu from 90 days in advance. There are also other possibilities to book, possibly also earlier than 90 days in advance, please see this post:

Reservations for domestic trains in Spain are not available online. Known possibilities to book are listed here:

I have an Interrail pass already but I can’t make a reservation? the date I need it for is 10th July which is less than 90 days….

90 days is the earliest that reservations for the Paris - Barcelona train are available from Interrail, you can book them right up until the  day of travel or the train is fully booked.

Internal Spanish trains have restricted sources of reservations as described in the above links, you will most likely have to wait until you are in Spain to book these.

Thanks so much - I think the Paris-Barcelona train is booked as cant see any options to book using my Interrail pass. Think I might be better getting a refund for the pass and then booking everything individually!

Do not get a refund.

There are seat reservations for 37€ !!!

While tickets for this leg cost at least 200€ (it is extremely expensive because SNCF basically has the monopoly at the moment)

Maybe you haven't added your pass to eurail.com

So strange - looking to go Paris to Barcelona on 6th July and cant see anything available!

On 6th July there are only 1st class seats on the morning train and both classes in the afternoon.

On 10th July both classes on all 3 trains of the day

Thank you - can you see this on the Interrail site? will look again!!

Availability for passholders is the same as for general sales on this route. There are no standard class tickets left on the morning train on 6 July with the cheapest ticket available being 1st class at €269

Passholder reservation is €37 through Interrail.

Passholder booking through Interrail https://www.interrail.eu/en/book-reservations?

Yes we can all hope RENFE will start services this summer from Lyon (+ accept passes), otherwise it'll soon be impossible to travel from Paris to Barcelona all summer without taking the Portbou route… Regular tickets are soon booked out on some days and cost more than 200€... SNCF pffff