Thread 'Travel from Biarritz to irun' https://www.caminodesantiago.me/community/threads/travel-from-biarritz-to-irun.82540/
Personally, I'd start walking from the airport...
https://www.gronze.com/francia/pirineos-atlanticos/guethary/gite-pelerins-geo
This is a grand gite for your first...