Protected Biotope

The tidal platform and the flysch cliffs

The coastal strip located in the western part of Gipuzkoa's coast, between the villages of Deba and Zumaia, covers around 8 kilometres of cliffs. In this spot mountains descend abruptly to the sea forming one of the most spectacular natural areas in the Basque Country: the Flysch.


Besides, this strip includes elements of geological and geomorphological value with an internationally recognised prestige, as well as the richest and most complex marine ecosystem in the entire Basque coast. All these natural values have had an excellent conservation due to the difficult access to the area. For this reason, in 2010 it was declared as the Basque Coast Geopark together with the inland karst area.


Its high cliffs rise over a peculiar phenomena known as the tidal platform, also know as "Flysch". Over thousands of years, the sea waves have eroded the smooth clayey materials of the flysch, sculpting the amazing cliffs that form a plain surface on the coastal line. The horizontal platform consists of an endless sequence of sharp and quirk rock layers shaping a real visual caprice.


Due to the earth's movements in the Cretaceous Period many of this layers that were originally horizontal, turned upright. Thus, in the Mendata, Sakoneta and Pikote areas we will find the most abrupt cliffs.


The layered materials of the flysch represent a first-rate geological sanctuary at an international level. Worldwide geologists study this phenomenon as it gathers all the information about the main climatic, biological and geological events of the Earth for 50 million years.


Besides, the cliffs on the Itzurun beach are considered the best spot to analyse two key moments in the Paleocene. A new world to discover in an exciting journey in time.



The Algorri Interpretation centre and the Zumaia Tourist Office offer a complete range of hiking routes, geological guided tours, visits and boat trips through the biotope. Begi-Bistan, an active tourism company, also offers activities related to the environment. Phone: 657 794 677

Information of interest

Protected Biotope

Algorri Interpretation Centre Phone: 943 143 100 E-mail:

Zumaia Tourist Office Phone: 943 143 396 E-mail: