ISO coastal Mediterranean town to visit with grandparents

My family will be in Barcelona in October. From there, we plan to travel to a coastal Mediterranean town, where we can meet up with our grandparents and spend some time relaxing. My grandparents are in great shape and very active.

We did this a few years ago in Positano, and we appreciated that there were enough restaurants and activities to enjoy, but it was not a metro city.

So far, I have researched Mallorca and Canary Islands in Spain and the Madeira, Azores, and Algarve areas of Portugal. Also some areas of Croatia and Montenegro. Everything is starting to blend together and become more confusing.

I would appreciate any further suggestions and personal experiences.