Help needed with 3 week itinerary Barcelona to Barcelona loop

Lots of very similar discussions on the forums for easy reference.

Generally, you’ll get better advice if you do some research, clarify some goals/objectives, and assemble a draft itinerary for feedback.

Barcelona is a large city with lots of interesting and important sites. I would spend at least 6 nights in Barcelona.

Then rent a car and drive along the Costa Brava. For how long? It depends on your interests. You could easily spend a week exploring Costa Brava. Stop in Tossa de Mar, S'Agaro, Callela Palafrugell and there are many other places on the coast. I know people like Begur and spend several nights there. Spend a couple nights in Cadaques, a white-washed village that resembles a Greek fishing village. From Cadaques, you can visit Dali's home in Port Lligat, drive to stunning Cap de Creus, (a natural park).

You can then spend several nights in Girona, a medieval walled city. Then drive into Northern Catalonia to see the Pyrenees and towns such as Besalu, Ripoll, and Rupit. We spent one night in Cadaques and 2 nights in Girona and wish we had more time.

San Sebastian and Bilboa are possibilities, too, but I haven't been there so can't offer any first-hand advice.

I have a number of places on my “to see and do” list for that area; going west almost to Zaragoza, north to the border, and south to the area near Tortosa, but where I want to visit may not be where you want to visit. As Scudder suggested, knowing your likes and dislikes would be helpful.

Yeah, it's like asking, "I have 3 weeks to see America. Where should I go? Please include hotels recs."

You'll get much more useful advice if you share what your interests are, your preferred travel style, budget, pace, and why you want to visit Spain?

Finally: The flights you booked in to and out of Barcelona are not etched in stone (flights can always be changed, and sometimes it makes sense to do so even if it ends up costing a little more to make a change), since flying in and out from the same city will limited your itinerary options. It might work out best to keep the flights you have, but you need to look at that in the context of the rest of your trip to make the optimal choice.