The Bidasoa is a river running from Navarre to the Basque Country which marks the border between France and Spain at the city of Irún.

It is precisely its status as an international border, together with the railway which runs alongside it, that gives the river its special character.

The Bidasoa Greenway makes use of part of the route of the now defunct Txikito Train (which used to run from Elizondo to Irún) and provides a memorable journey through the picturesque towns and villages along the banks of the Bidasoa.