Hello LTfit,
I just had a look for flight tickets (one in May, one in June) -
flight from Amsterdam to Biarritz . No direct flight & prices (one way) are from 550€ upwards.
flight from Amsterdam to Bordeaux . Air France direct (but expensive). British Airways via London at a reasonable price (opodo.be)
From Bordeaux, you still have to take a train to Bayonne. And from Bayonne to Saint Jean.
Alternative : train via Brussels or Paris.
I just had a look on
http://www.tgv-europe.nl
Here what I found (May) :
11h16 - AMSTERDAM CS
14h35 PARIJS NORD (THALYS)
15h45 - PARIJS MONTPARNASSE 1 ET 2
20h48 BAYONNE (TGV )
Reisduur 09h32
90.00 € (SMOOVE : Ticket niet omruilbaar of terugbetaalbaar.
TGV Prem's : Ticket niet omruilbaar of terugbetaalbaar.)
De laatst beschikbare plaatsen!
NB this would mean to stay overnight in Bayonne, I guess, as you arrive late.
Good luck, and buen camino!
Fatma