Following the awarding by UNESCO of Biosphere Reserve status to URDAIBAI the Basque Parliament passed the Urdaibai Biosphere Reserve Protection and Structuring Act (Act 5/1989).

To implement this act and thus protect and recover all the ecosystems in the reserve, the PRUG (Master Plan for Use and Management) was passed as Decree 242 of 3rd August 1993.

1998 saw the passing of the PADAS (Plan for the Harmonisation and Development of Socio-economic Activities – Decree 258 of 29th September 1998). Like the PRUG, this plan is a regulatory instrument for the implementation of the Protection and Structuring Act.

In 1997 a Plenary Session of the Governing Board approved the Management Plan for Interpretation, Research and Environmental Education.