Thank you very muchI would either walk or take a bus from the airport to Biarritz station (about 1.5km) and then a local train to Hendaye. You can walk from there into Irun (about 2km) or take the local Euskotren light railway from Hendaye.
PS. Alternatively you can take a no.3 bus directly from the airport to Hendaye.
Thank you so much ,I arrive on the 10 th mayYes, get the number 3 bus and get off at Hendaye railway station. Then walk across the bridge into Irun.
If you have time you can walk on the riverside path following the Bidasoa inland to Behobia where there is also a bridge.
Or get off the bus at Hendaye beach and then take the foot ferry across from the marina to Hondarrabia