I’ve had a few questions related to SIM cards. So this was my experience based on walking the Camino Frances in 2015 (From St Jean).
I pre purchased SIM cards for France and Spain. I didn’t want to wait until hitting the first major town before being able to get a SIM card.
The French SIM I used for a few days in France and in St Jean. Then swapped over to the Spanish SIM when I got to Roncesvalles. Both SIM’s worked well. Both included voice and data.
The French one I bought from: Le French Mobile
and the Spanish one from: SimCardSpain
I ordered these before I left Australia, and they just arrived in time. Took 7-10 days. I would use both these companies again.
It took me a while to work out how to ‘recharge’ the Spanish one…. I used a lot of data uploading videos to my blog, calling my wife on Skype etc. Most small shops do the recharge! Just ask for ‘Telefono Recarga’. Hand over 5e 10e or whatever you need and tell them the network you are using. I used Vodafone. They will do the recharge and you’ll get a text message telling you the recharge amount and how much credit you have remaining.