3 weeks itinerary south of france and northeast spain

We’re planning a similar itinerary for summer 2024 (not for as long), and Nice is my favorite place in France.

On previous trip, we visited Les Baux while staying in Saint-Remy-de-Provence.

We want to explore more of both French and Spanish Basque country, and will probably have a rental car, for covering locations. We’ve just started planning, so don’t have much of those locations identified. On a trip a few years ago, we stayed in both Bilbao and San Sebastián (aka Donostia), and stayed in the Old Town of each city. San Sebastián’s aquarium was a great place on a rainy day.

I am not sure that 3 weeks is enough time for what you intend to visit; here's my math:

• Nice & vicinity : 3-4 days
• Avignon/Aix and vicinity (Provence): 4-5 days
• Lyon: 2-3 days
• Chamonix/Annecy: 3 days
• Carcassonne: a day
• Dordogne: 4-6 days
• Bordeaux: 1-2 days, 3 if day tripping to Arcachon or vineyards
• Basque country (both sides of border): 1 week

That's 3.5 weeks at a fast pace, and you'd need 4 at a more reasonable pace.
If you cut Lyon and the Alps, which are a bit of an outlier, then you could pull it off: a week for Nice and Provence, a week for Carcassonne-Dordogne-Bordeaux, and a week for the Basque country.
You'd need a car for the Dordogne (unavoidable) and it is highly recommended for the Basque country and in Provence.

Three weeks or three months? If you’re going for three months you cannot exceed 90 days in the Schengen zone. Make sure you exit a few days before in case air travel is interrupted. If you stay longer than 90 days you will be fined and possibly denied re-entry back into the zone.
If you plan on driving between France and Spain make sure you can take your rental car across its borders. This train can also get you there and back if needed: https://www.euskotren.eus/en.

This sounds like a really great trip! As a previous poster mentioned, make sure you are there less than 90 days in 180 (unless you have EU citizenship then it doesn't really pertain.) But, you should be able to be able to see all of these places in that timeframe without it being too rushed. We spend half the year in the SW of France (just outside of Bordeaux) and you will want a car to explore the Dordogne, Biarritz, Lescaux (and the other wonderful caves) as well as driving down to San Sebastian (it's an easy 2hr45 min drive.) So much to see in this area if you drive. Many of the towns on the Med are easy to visit via train. Also, consider the time of year you're visiting. Many of these places are super crowded during high season, but lovely during shoulder season. Also easier to rent cars and you don't have to worry about purchasing train tickets right when they become available (especially on popular routes.)

Thank you for all your advice. I'm well aware of the 90 days and are exiting France before that time frame. I've been thinking of Chamonix and Annency in maybe April if we can fit it in. If not, c'est la vie. Thanks for the tips on on rental car vs not. I figured we'd need a car during a portion of that.

April is not a great time to go to Annecy and Chamonix: beyond ~10 April is too late for most winter activities (except ski mountaineering), and it is way too early for summer activities.

Thanks Balso. I was wondering on timing because of the snow. But hey, we go to Yosemite in the winter. Will probably leave it for another time. Maybe incorporate in an Italy/Switzerland trip. I still have my eye on visiting lavender in July (height of season, so that's why haven't done it before).