I must point out that most hardcore bands that are active today wouldn't even exist if it hadn't been for hardcore's predecessor, a brand of punk rock called "rock radikal vasco".
These are the pioneers of the spanish punk scene in the 80s among others...
*Before I start throwing names you should know that the Basque Country is divided into 3 areas: Bizkaia, Guipuzkoa and Alaba, and their capitals: Bilbao, San Sebastian and Vitoria (class dismissed hehe)
Now, truth be told since then, punk rock bands have populated the underground, but there's always been shortage of real hardcore (of any school). That being said, the scene is most alive in Bilbao and its surroundings with the B8 Crew.
The San Sebastian area (where I'm from) however is known for a proliferation of crust, powerviolence and grindcore bands (there's a lot of powerviolence bands in the small town of Zarautz for example).
Vitoria saw the birth of one of the most influencial bands in the history of metal and hardcore in this country: Soziedad Alkoholika (they are crap now, but their first two albums are amazing).
Bottom line is there aren't tons of true hardcore bands in the basque territory, but here's a quick list (not all of them remain active, some disbanded years ago):
- Crickbat (Bizkaia - old school hxc)
- J.A.N. (Bizkaia - fast hardcore)
- Justa Venganza (Bizkaia - tough guy hxc)
- Justice Department (Bizkaia - Vegan metalcore)
- Zartako (Bizkaia - Antifascist hardcore)
- Fourscore (Alaba - hardcore)
- Nous (Guipuzkoa - old school haxc)
- Antihero (Guipuzkoa - powerviolence)
- Erantzun (Guipuzkoa - fastcore)
- Goddammit (Guipuzkoa - fast hardcore)
- Kobory (Guipuzkoa - dirty crustcore/grind)
- Anosognosia (Guipuzkoa - grindcore)
- Ira et Decessus (Guipuzkoa - fastcore/powerviolence)
- Hell Division (Guipuzkoa - D-Beat)
- Squassamento (Guipuzkoa - fastcore)
- Metralleta (Guipuzkoa - powerviolence)
- Txixaparrazta (Guipuzkoa - fastcore)
- Adrenalized (Guipuzkoa - melodic hxc)
- Materia (Guipuzkoa - metal hxc)
That's all I can think of for now. As you can see, not much proper hxc, kinda sad. I'm sure there's more and some I know have probably slipped my mind, but it's a good start.