What’s your exact route looking like?

I presume you want to take the AVE from Lyon? That’s indeed only to be bought with the train personnel when the train is on the platform.

The TGV Paris-Barcelona should be reservable online, doesn’t stop in Lyon, but does in Nîmes, Montpellier, Perpignan,...

We don’t have to go through Lyon; that just seemed to look like the best option at the time, based on price and timing.

If you mention the exact route and trains you plan to take, we can help you figure out alternatives.

13th of march doesn’t seem like a busy travel day, so probably you can risk it just buying reservations for the AVE on the platform in Lyon. But, it’s a stressing factor though.

Trains between France and Spain are very infrequent. Very annoying.

Thanks for the help!

Ultimately, it just needs to be: Amsterdam → … → Barcelona

But I have been looking at doing the following because we can use IC trains between Amsterdam and Bruxelles-Midi without seat reservations:

Amsterdam → Bruxelles-Midi

Bruxelles-Midi → … → Barcelona

The connections between Bruxelles-Midi and Barcelona don’t really matter, except that we’re trying to avoid having to travel across the city (e.g., in Paris) because we’ll have a lot of luggage with us.  Oh, and there are six of us :)

The eurail.com site says, with regard to calling Renfe, “Pre-reserving a seat is possible. You will receive a PNR code which you must use to pick up and pay for your reservation at a local station ticket office, making sure to show your Eurail Pass.”  But based on my phone call, that doesn’t seem to be a thing.

Okay, I’m going to puzzle a bit. I’ll get back to you ;)

If you want to use Eurostar Brussels-Paris or TGV Brussels-Lyon, then you need to book reservations ASAP since availability is limited (for this TGV very limited even).

Okay: I’ve found an option. Very long travel day though @cdeccio 

• Dep 06:28 Amsterdam C to Brussels via reservation free IC
• Arr: 09:17 Brussel-Zuid/Bruxelles-Midi
• Dep 10:17 Brussels to Valence TGV (by TGV, 20 eur per seat reservation on rail Europe)
• Arrival 14:48 in Valence TGV
• Departure: 16:57 in Valence TGV to Barcelona (TGV), arrival 21:27. (25 EUR per seat reservation according to rail europe).

Note that there’s not much to do in Valence TGV (don’t go to Valence ville, long distance from the tgv station!)

If you split it up in raileurope (Brussels-Valence TGV, Valence TGV-Barcelona) you should be able to book it online.

Book it asap though!

An Alternative option would be:

Continue your journey with reservation free trains from Amsterdam-Antwerp-Lille (fr) and get a direct TGVthere to Montpellier/Nîmes from there (10 or 20 EUR seat reservation). Spend the night there and continue your journey via TGV to Barcelona the other day, or reservation free regional trains, by changing in Perpignan in Portbou.

Would look something like this when staying the night in Nîmes and continuing by regional trains:

Thanks!  I’m looking into this now and will report back.  I also need to see if I can exchange the seat reservations I already purchased for TGV between Bruxelles-Midi and Lyon

Honestly I'd go via Lyon : there are 160 seats left right now so the train won't fill up by then. I'm pretty confident. You might not all sit together but right now most carriages are empty. Really not a busy day as said by Brendan!

Staff is used to selling them on the platform, Lyon is also the departure station so you'll have enough time to speak to them!

@thicab thanks for the suggestion!  We will only have 30 mins between our arrival and scheduled departure in Lyon.  That makes me a little nervous.  Also, a family member just stopped by the ticket office in Lyon, and they told her that they only have 5 or 6 seats for passholders on a given train.  Does that sound right?

No, that's wrong. There is mostly SNCF staff at the station and as they're competing with RENFE they won't be helpful. At all.

The AVE doesn't even appear on SNCF planners…

The family member could however see RENFE staff at the platform when the train arrives from Spain at 13:30 but that's maybe a bit much to ask... :)

So, to be clear, if I am to purchase the seat reservations at Lyon, I just go straight to the platform itself and purchase them there -- and not at the ticket office?  I just tell them that I have a eurail pass and need a seat reservation?

Exactly, that's it. Just ask the train staff.

I just wanted to report back on this.

We arrived at Lyon Part Dieu with 25 mins before the train to Barcelona was scheduled to depart.  We easily found the platform and then waited for the train to arrive.  When the train arrived, the staff exited the train, and we asked one of them about tickets for Eurail pass holders.  They were very kind and very helpful!  And, as you suspected, there were plenty of seats.  We had plenty of room to all sit together, and there was a lot of room for our luggage.  Everything worked out great!  Thanks so much for everyone’s useful advice!