Travel from Santiago de Compostela to Bilbao?

Hi,

There is a bus service with Alsa. The website is http://www.alsa.es/en/

or

train with connection in Ourense. Spanish Rail (RENFE) website is
http://www.renfe.com/EN/viajeros/horarios.html

Journey for both options will take most of the day.

If you have the time and the inclination, you may also be able to use the narrow gauge railway from Ferrol all the way along the coast but I'm not sure what connections are required. See http://www.feve.es

EDIT: Journey by FEVE can be done Ferrol - Oviedo - Sanatander, then Santander - Bilbao but not in a single day.

I'm at work at the moment, but drop me a PM if you need further help and I'll try to do so later.

Regards
Mig