Itinerary help Basque Region France/Spain 9 days

What an amazing trip!
My experience is not recent- at least 10 years ago. I also traveled solo on a budget and used only public transportation.
I based in St Jean de Luz ( loved it) and did day trips to Biarritz and Bilbao. I also went to Sare for a hike.
From Bayonne ( the museum was fantastic) I took the train to SJ Pied de Port. I stayed a couple of nights and loved that, too. It might be too far for just a day trip?
I think from there I went to San Sebastian, and also stayed a couple nights. It was expensive, but I used a private guide to drive me along the coast south, with another hike.
I'm pretty fluent in French. The language change, if still the same, was quite abrupt at the border and signs. Most were in Basque first, then Spanish but I don't remember having navigation challenges and it was before Google maps or other navigation apps!
It was one of my favorite trips!

Thanks Bon Voyage! I may just copy your itinerary. Do you have recommendations for your accommodations? I don’t suppose you still have the info for the private guide?

I will try to piece it together for you from my old-school photo album, circa 2012- that's how long it's been! I'm glad this may be helpful.
From the US I flew into San Sebastian/Donastia and by taxi stayed overnight in Hondarriba in an old and very charming room. Explored the castle, acclimated to local time.
Early the next morning there was a small boat to cross to Hendaye for the train, and I think a transfer at Irun to get to St Jean de Luz.
I stayed in a wonderful hotel quite close to the beach- sorry I don't have names! I was there 3-4 nights as my base for day trips. One day I used a bus tour (essentially just the ride to Bilbao and back with several hours in between) to see the Guggenheim. I was a little rushed to see anything in the city, but walked a bit.
Another day I took a very early local bus to Biarritz. It was cold and threatening rain and windy! A half day was just right to see the beach and look at the stores and walk to.... there's a famous home? I don't remember.
Another day I used the bus again to go to Sare and le Petit Train de la Rhune. It's an old cool wooden cog wheel train. There's a cafe at the top and you can hike down. Warning!
I was excited to maybe see a Pottok Pony along the way. Initially the trail was obvious and clearly marked (paint marks). Suddenly, the densest fog I've ever seen rolled in. I literally couldn't see more than a foot in front of myself, let alone the trail markings.
This was the trip I learned to not hike alone!
I somehow literally ran into a young French couple and followed them down to the train station!
Then I took the train to Bayonne, toured the Basque Cultural Museum and then the train on to SJ Pied de Port. I think it was almost 3 hours? Maybe 2. As a day trip you'd need an early start.
I loved staying overnight, I think I stayed 2 nights. Although not favored in the RS guidebook I just loved it. It was also an opportunity to walk some kilometers on the Camino.
Then back to Donastia/San Sebastian. Fascinating to learn more about Basque culture and the political aspects. I stayed (2 nights?) The Peine del Viento is a striking metal piece by Chillida to see at the far end of the beach.
The hotel a couple blocks up a hill from the beach. I only have "Jon" for the private guide. We drove south down the coast and saw Cumaia and Loyola and then the hike with incredible overlook at Mt. Ernio.
The guide was the most $$$ thing I did but totally worth it for how much I learned and it was like touring with a friend (albeit hired!).
Happy planning! Hope this helps!

The fastest public transportation from San Sebastian to Bilbao is by bus. The buses are frequent enough to be convenient. The train route is scenic and worth taking one way if you happen to have the time, but you're on a train that stops everywhere, and the trip is very slow. I preferred Bilbao to San Sebastian.

I also preferred Bayonne to Biarritz.

Thank to you both! Yes, it appears that I will prefer Bayonne to Biarritz - but since I’m there, I feel like I should at least take a look around the beach and town, but not stay in Biarritz. And thanks so much for all the details! Very helpful, even though it was a decade ago!

hey hey lurag.trip
happy to hear you're visiting the basque region.
my BFF is french basque. from small village near st jean pied de port. seen her pictures which are gorgeous. maybe look for a day tour to check out those villages. couple posters are from there and hope they come on board for info.
eatingeurope.com/ san sebastian
has a special for 30% off, many have bought a gift card to use later. maybe something you'd like to do.
solosophie.com/ a guide to the best things to do in saint jean de luz
have a great time and enjoy. my friends love the area with family still living there
aloha