The Best of Basque

Discover La Ruta del Flysch, between Deva and Zumaia

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When we talk about a place that combines fascinating geological history, scenic beauty, and a rich cultural heritage, the Deba-Zumaia Route in the Basque Country, Spain, is a destination that cannot be overlooked. This coastal stretch of 14 kilometers, which can be completed in approximately 4 hours, is a natural gem that offers a unique experience for nature and adventure enthusiasts.

Duration: 4 hours
Length: 14 kilometers
Difficulty: Medium
Elevation: 183 meters
Cumulative Elevation: 649 meters
Start and Finish: Deba-Zumaia

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Discovering a Geological Treasure

The Deba-Zumaia Route is much more than a scenic hike; it is a journey through millions of years of geological history. This coastal section of 8 kilometers and 4,299 hectares is a window into our planet’s past, where rock layers reveal secrets dating back over 60 million years. The erosion of the sea has exposed these rock strata, which are key to understanding significant events in Earth’s history, such as the extinction of the dinosaurs. This is a testament to the wondrous work of nature that we must protect and preserve.

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Points of Interest on the Route

Santa Katalina Hermitage

Located at the top of the mountain, the Santa Katalina Hermitage offers a stunning panoramic view of the Basque coast. Its history dates back to 1539, and in the past, masses and pilgrimages were held in honor of Santa Catalina and San Juan. Today, the tradition continues with the celebration on June 24, the feast day of San Juan, where attendees are welcomed with a “hamaiketako” by the residents of nearby farmhouses.


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Mendatagaina is an exceptional viewpoint located between the two main geological domains of the biotope. To the west, the layers of black flysch are subparallel to the coastline, resulting in homogeneous erosion. To the east, the calcareous and sandy flysch is arranged perpendicular to the cliffs, causing differential erosion.

Cape Caves

The Aitzuri Cape Caves, located at the base of the cape of the same name, are two impressive cavities with large entrances, approximately 15 meters wide and 20 meters high. Erosion has created these caves along fractures of varying directions, related to the nearby Andutz Fault. These fractures represent planes of weakness that the sea has attacked more easily, forming gaps parallel to the geological layers.


Algorri is a picturesque spot with little sand and numerous rocks that emerge as the tide rises. This place is a gem in itself and is worth a visit, especially in summer when the sun sets on the horizon of Matxitxako, creating a stunning landscape.

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Andutz Fault

The Andutz Fault is one of the main tectonic features in the geopark and is especially visible at the tip of Mendata. This fault separates two major flysch units in the geopark: the black flysch from the Lower Cretaceous in the west and the Cretaceous-Tertiary sequence in the east. This geological contrast creates one of the most spectacular cliffs in the geopark, known as the Aitzuri Wall.

Sakoneta Tidal Platform

The Sakoneta Cove boasts one of the best flysch formations on the tidal platform between Deba and Zumaia. In its cliffs, originally horizontal strata are shown in a vertical position due to internal earth movements that occurred 40 million years ago during the Alpine orogeny. This geological phenomenon is a true treasure for geology enthusiasts.

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San Sebastián Hermitage in Elorriaga

The San Sebastián Hermitage played an important role on the Coastal Way of St. James and its history dates back to the 10th-11th centuries, according to historical references. Inside, notable elements include the Romanesque baptismal font, the image of the Virgin Mary from the 13th-14th centuries, and two small sculptures of San Roke and San Sebastián. This site is a testament to the rich cultural heritage of the region.

Itzurun Beach

Itzurun Beach, open to the Cantabrian Sea and located in the shadow of the hermitage of San Telmo, patron saint of sailors, is a place that combines natural and cultural beauty. Additionally, it has ISO 14001 certification due to its commitment to sustainability. From its dark sands, you get a complete view of the coast of Bizkaia to Matxitxako.

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Overview of the Route

The journey begins next to the Deba Town Hall and goes through narrow streets to reach the parish church. From here, you descend via a staircase that leads to San Telmo Street. Then, you continue until you reach the hermitage of the same name, located on the cliffs of Itzurun Beach. This initial stretch offers breathtaking views of the cliffs and the sea.

After enjoying the beauty of the cliffs, a gentle descent begins, taking you practically to the seashore. From here, the route ascends via a narrow path, entering a small valley. The ascent culminates when you reach the road coming from Zumaia, leading to the nearby farmhouses Andika Zahar and Andika Berri.

From these farmhouses, you advance briefly on the asphalt road and then take the dirt path leading to the small Etarte pass. The ascending path takes you to Galarretako Zabala, in the Elorriaga district, where there is a recreation area with tables and benches. At this point, you are about to visit the San Sebastián Hermitage.

After leaving behind the Elorriaga district, trail signs lead you to a valley near the Txakotegain and Sorazumendi area. Descending, you head toward the farmhouses Arantza Goikoa and Arantza Bekoa. From here, the path descends almost to the coastline, crossing the small Errotaberri stream to reach Sakoneta.

Starting from Sakoneta, you begin to ascend toward the farmhouse of the same name, offering spectacular views of Sakoneta and Mendata coves. In front, you can see the eastern face of Punta Mendata, known as Aitzuri. You continue descending toward the railway tracks, passing over the tunnel and heading toward the Mendata farmhouse.

Following the trail parallel to the coastline, you begin to see the western face of the imposing rocky mass of Aitzuri. From Itxaspe, you descend along the trail that leads to the Atalaia area and subsequently Aitzuriaurre, finally reaching the Arronamendi valley. From here, you start to ascend until reaching the N-634 road near the panoramic viewpoint of “La Salve.”

You cross the wooden walkway and take the trail leading to the Santa Catalina Hermitage. After a well-deserved rest and admiring the stunning views, you follow the path that takes you to the farmhouses Etxeberri and Iparragirre. It is recommended not to descend along the cliffside path as it is closed and dangerous. After passing these farmhouses, you continue on the trail marked with red and white GR signs, descending until you reach a cemented path next to the San Roke Hermitage. From here, you descend steeply until you reach the historic center of Deba.

The Deba-Zumaia Route is a journey that combines unique geological history with stunning scenery and the rich cultural heritage of the Basque Country. This 14-kilometer hike is an unforgettable experience for those who wish to explore nature at its finest and immerse themselves in the Earth’s history.

Each point of interest along the route tells a unique story, from the Aitzuri Cape Caves that reveal geological secrets to centuries-old hermitages that attest to the region’s rich cultural heritage. If you are seeking an adventure that connects you with nature and transports you through time, the Deba-Zumaia Route is an option you cannot miss. Get ready to explore and discover a world of geological wonders and breathtaking landscapes in this corner of Spain!

Author Profile

Irene was born and raised in Bilbao. She has a deep rooted passion for her country and culture. She has a Bachelors degree in education and has traveled to over 85 countries throughout the world.
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