It’s possible on both dates to go. E.g. via Paris (departs from there 14.42 both days directly to Barcelona).

Best connection is on monday: 7.58 directly from Rotterdam to Paris and 14.42 directly from Paris to Barcelona. Possible at www.raileurope.com (just split the booking).

The 14.42 from Paris is also available on sunday but you need to book a slower route to Paris as the direct trains are sold out (e.g. 7.11 from Rotterdam via Antwerpen and Courtrai to Lille Flandres; 12.05 from Lille Europe to Paris; 14.42 from Paris Gare de Lyon to Barcelona).

But maybe you are trying to book the direct train from Lyon? That’s not possible to do online. 

As you probably know there are holidays in the Netherlands so some trains are already sold out. However it is still possible to do the journey.

On top of that Eurostar trains have a passholder quota. Book the expensive Eurostar from Rotterdam or Brussels ASAP or take the slower but cheaper route via Lille (feel free to ask for advice).

Look one train at a time so you see all options.

Afternoon departures are available from Rotterdam or on Monday early morning too. A few more from Brussels which you can reach with the hourly Intercity-Direct.

Via Lille it would look as follows :

- ICD Rotterdam Centraal - Antwerpen-Centraal 08:11 - 09:16

- IC Antwerpen-Centraal - Kortrijk - Lille-Flandres 09:36 - 11:51

- quick walk across the square or you leave Rotterdam an hour earlier and have a little break :)

- TGV Lille-Europe - Paris-Nord 12:05 - 13:24 10€

- RER D between stations (Interrail not valid)

- TGV Paris Gare de Lyon - Barcelona-Sants 14:42 - 21:27 35€

Maybe also possible to avoid Paris, boarding a TGV in Brussels (passholder quota) or in Lille.

Third option via Marne-la-Vallée (Disneyland) :

- ICD Rotterdam Centraal - Bruxelles-Midi 07:11 - 09:16

- TGV Bruxelles-Midi - Marne-la-Vallée 10:17 - 12:08 20€

- RER A to Gare de Lyon (Interrail not valid, 5€ ticket)

As you can see this route towards Spain is very popular and especially does not have many trains...

Thanks for your advices. I'm now studying the alternatives that you have suggested.

• The Eurostar from Rotterdam (at 6:58 or 7:58 AM) doesn't seem to be available for Interrail Pass. It indicates: Rail Pass doesn't apply for this trip. Is the indicated price than the full price without Interrail pass?
• However, there seem to be IC Direct alternatives. Do these have extra costs with Interrail pass?
• When it indicates: “Seat reservation has to be done at station ”can this be any station? So also in the Netherlands?
• Are the rates indicated on Raileurope.com the extra costs only?

Both Eurostar services do have availability for 4 adults from Rotterdam to Paris (29.4.2024). The price is 128 € 2nd class or 148 € 1st class for 4 persons. Thats’s the reservation price for passholder. But it’s not available on sunday (28.4.2024).

I do get this message (Rail Pass doesn't apply for this trip) just for the 8.58 departure (or later ones).

If you’d like to go from Rotterdam to Paris via Lille, you do need (just) a reservation for the TGV.

For the message “Seat reservation has to be done at station” it depends for which train you do get the message. If it’s for the AVE from Lyon to Barcelona, it has to be a station in Spain. 

The problem with Raileurope is that it*s showing normal price when there’s no passholder fare available So there’s no general answer for this. But it’s indicated when having a look at the dropdown menu with prices.

I found that one too now. So to Antwerpen or Brussel no prices/seats available, but to Paris there are. Well that works for us….

Than the next part. Via Lyon is faster than from Paris straight to Barcelona. 

How can I then add the reservation from Lyon to Barcelona? It reads: “Seat reservation has to be done at station”

You can’t. It’s not possible online. Just at train stations in Spain. You may try to buy the mandatory reservation from the train conductor before boarding in Lyon.  

Do you mean that for travelling from Lyon (France) to Barcelona (Spain) you pay the extra fee in Spain?

Or do you mean that we can do the seat reservation and payment of the fee in Lyon?

No, you can’t buy this one in Spain after arrival and you can’t buy it in Lyon at the counter; the only way would be to search for the conductor of the train before boarding the train in Lyon and ask if it’s possible to buy a reservation. This may work or not... 

Personally I’d prefer the direct train from Paris...

Reading this now: 

Yes as Hektor said reservations for the AVI are only available at Spanish train stations or by asking staff on the day. RENFE (the operator) doesn't really like Interrail passholders, let's put it that way...

Staff can sell folding seats if the train is full but I would say it's a bit risky on busy weekends + during summer.

The route via Paris is quite expensive I agree. To save money you can cross the border on a regional train. It's a lot slower though.

Also possible would be to take the night train from Paris to the Spanish border : afternoon Eurostar for 32€ + couchettes to Latour (Pyrénées). The following morning either use a pass day or buy 13€ tickets for the regional train to Barcelona. Arrival at 13:30.

EDIT : if you wish to travel on Sunday morning this is possible →

- ICD Rotterdam Centraal - Bruxelles-Midi 09:11 - 11:16 (reservation-free)

- Eurostar Bruxelles-Midi - Paris-Nord 12:16 - 13:38 27€

- RER and then direct TGV to Barcelona for 35€

It would be cheaper but longer via Lille.

It sounds somewhat vague without any guarantees on getting in…... 

So we will have to decide to take the TGV from Paris to Barcelona and arrive at 21:27.

Or go via Lyon with more uncertainty and hope to arrive at 19:34.

Is the IC Direct from Rotterdam to Brussel without extra costs? As it says seats reservation to be done at station.

For this option: night train from Paris to Latour (Pyrénées) on Sunday April 29th.

Raileurope doesn't provide your option for Monday April 29th.

Yes reservation-free. They're not possible at all like regular Dutch and Belgian trains. Hop on and sit wherever you want.

Let me check for the night train now.

Possible on both nights. Raileurope does offer this. 22.06 from Paris Austerlitz on sunday, 21.40 on monday. 10 € seat, 20 € couchette per person.

Sorry for the confusion. The night train I found. I meant how to continue from Latour to Barcelona on April 29th. I don't get that one.

Here’s the timetable: untitled (gencat.cat) - it’s not in the rail planner.

Have a look for La Tor de Querol.

Possible connection at 10.26.

Thanks. Does this has extra costs or can you use it with the interrail pass?

The interrail ticket is valid but you'd need a new travel day. And there are no direct trains to Barcelona city; you need to go by bus in between.

It's an interesting route because of the scenery but not the fast way to get to Barcelona.

OK, a serious option then.

Thanks for all your help, Hektor, thibcabe!