Mountains and Sea- Round trip to Southern France from Cantabria

Near Foix there is a park of prehistory, with out door exhibits and a small museum. They have hands-on experiences geared toward children. Sorry that I can’t be more specific about the location, but we visited many years ago. Try google.

Thats amazing - thank you ! would never have thought there would be something so child friendly

Looks fabulous

I was in the Languedoc to Bordeaux area last June. Languedoc has really nice forests, rolling hills and farmland with many 13 century castle ruins on the hill tops. I camped walking distance from Carcassonne and walked into the cite only at night.

Some of my favorites in the area of Carcassonne included Foix castle. If they like climbing around on ruins, there are castle ruins to hike to: Queribus, Peyrepertuse and Puilaurens are some of the best.

Going north from Carcassonne my favorites included Najac, Cordes-sur-Ciel, Peche Merle caves and Conques. I wasn't a fan of Albi (great church but not much else appealed to me).

You might also like Narbonne and/or Sete between Montpellier and Carcassonne.

I don't have any children...

The Foix castle was closed as of 3 weeks ago for some major-looking work, but I was told the exterior work had just been completed, so maybe it will be open by next summer; the local folks didn't have a target date. Perhaps there's already some information on the castle website. The town itself has an appealing historic center.

I would not stay in Santander unless it's a matter of sleeping as close as possible to the gorgeous beach (understanding that on any given day there's a good chance you won't have warm weather). The city is simply not one of Spain's most attractive, and it's short on historic architecture as a result of a dreadful fire in the 1940s.

I haven't been to Andorra for 45 years, but by all accounts the capital city has taken on the look of an outlet mall (tax-free shopping), so I would not choose it as my base.

Although it appears you already have several ideas appealing to the children, I feel I should mention the Picos de Europa, an area of dramatic scenery--some of Spain's best--that seemed to have some sporty options (maybe canoeing on the river?). There's an alpine lift and I think a nice hike to an alpine lake. The old stone town of Potes is very picturesque but has clearly been discovered.

I definitely preferred St.-Jean-de-Luz to Biarritz, but don't expect to be the only tourists there. What I would consider swimming weather isn't guaranteed.

I liked Toulouse a lot, but my focus was on things that wouldn't appeal to the children. In any case, be aware that the city can be very, very hot in the summer. Albi seemed even worse during my 2017 visit, and it was only June. I haven't checked historical data to see whether my experience was unusual.

Thank you @Brad! Some great ideas for detours.
We are certainly including Carcasone

Thank you to the last poster also

Interesting update on Foix- thanks! We are going to focus on the first reply - and go to the prehistoric parc

We have decided to drop Andorra - others say what you do- and drop St Jean and Bilbao for a smaller beachside village outside San Sebastian

I also know what you mean about Santander- but there is something wonderful about a very humdrum city - it just seems to offer the most amazing quality of life compared to other ordinary cities elsewhere. I like to pretend I am in one of these extensive families with grandparents and aunties to fuss over children and take some of the pressure off. The beaches are wonderful, but so are the promenades, the gardens and play parks dotted everywhere. It is very easy. We have been to the picos before - this time we will be in the pyrrenes for our mountain fix
But I also like the little seaside towns outside Santander (comillas/ St Vincente de la banquera)

nothing mega touristic- but theres the charm!

I think you may like them too

Hello, for something not mega touristy but charming, in lieu of Andorra, consider stopping at the Val d'Aran, and then day tripping to the Romanesque churches of the Val de Boí, UNESCO World Heritage Sites. Or drive down to the historic Aragonese towns of Jaca and Huesca, in the foothills of the Pyrenees, and make a day trip to Loarre Castle (one of the oldest in Spain).