Pamplona

Difficult to answer before knowing: How much of a radius? How long will you be in Pamplona? Will you have a car?

The atmospheric hill town of Laguardia and the Basque capital of Vitoria-Gasteiz with its interesting medieval quarter are both between 1 and 1.5 hours away by car.

Olite and its beautiful castle. Estella-Lizarra and its medieval old quarter. Ujué (Uxue) and its fortress. And small but amazing Gallipienzo. Pamplona-Iruña can be visited in less than a day.

I’ll assume you’ll have a car. Briones, Laguardia, and San Vicente de Sonsierra are all near each other and can be visited on the same day along with Érmita de la Ascensión in Ojacastro and Ezcaray. If you had time, the small cathedral in Santo Domingo de la Calzada is a nice stop. If visiting it, ensure you see the chicken coop inside it and read about the legend behind it.

Olite and its castle/palace of the Navarro Kings is great to visit. Estella and Puente La Reina are nice to walk around as is the old part of Artajona. In Estella, visit San Pedro de la Rua with its carved serpent pillar and cloister. Near Estella is the Monastery of Iranzu, founded in the 12th century.

Between Estella and Pamplona are Alto de Perdón and Santa María de Eunate Monastery. Both are on the Camino de Santiago. Also near there is the wine fountain at Bodega Irache. In addition to dispensing water to the pilgrims walking the Camino it also dispenses wine.

Heading east from Pamplona is the Castillo de Javier and Monasterio de Leyre. If you like to take walks, near the castle is Foz de Lumbier.

There isn’t much between Pamplona and the French border other than nice scenery. Without a car it would be difficult to get to most of the places I mentioned in a timely manner.

We enjoyed our visit to Iruñea.
The fort. https://en.wikipedia.org/wiki/Citadel_of_Pamplona
The park.
Walking the path of the “running of the bulls”
Lunch at https://restaurantealhambra.es/