The flysch route

Zumaia - Deba (GR 121-Talaia)


Technical details

Maps and profile

Areas of general interest

Technical brochure


Download the GR 121 route

Track GPS - Wikiloc

Technical details

Duration: 4h

Length: 14 km

Difficulty: Medium

Change of elevation: 183 m

Accumulated change of elevation: 649 m

Starting and finishing point: Deba-Zumaia (or vice versa)

The protected coastline between Deba and Zumaia is 8 kilometres long and 4.299 hectares of peculiar, unique, spectacular beauty of outstanding scientific valueon an international level. It hides a singular treasure of natural beauty: over 60 million years of geological history written in successive rocky strata which, due to sea erosion, have been exposed and now show the keys to the understanding of some of the most important events in the recent history of the Earth, such as the extinction of the dinosaurs. It is a highly fragile habitat that we must protect at all costs.

Map and profile of the route

Areas of general interest

The hermitage of Santa Katalina


Situated on the mountain peak, it is a genuine watchtower from which you can make out a large part of the Basque Coast. The first references to this hermitage date bake to 1539. In the past, a mass was held and there was a procession on the days of Santa Catalina and San Juan. Nowadays, only San Juan's Day is celebrated (24th June) by the people from the nearby farmhouses.

Aitzuri cape caves


These are two large cavities formed in calcareous flysch at Cape Aitzuri opening way for multiple fractures in variable directions, related to the nearby Andutz fault. They are about 15 metres wide by 20 metres high and an extend inwardly about 25 metres.


Andutz fault


It has a N-S orientation, and although it affects alpine structures, it is likely to have a much more ancient origin. About 4 million years are omitted on the cliffs and the black flysch comes into contact with the calcareous flysch, giving rise to one of the great rock faces in the Geopark, the Aitzuri Cape.




Mendatagaina is an exceptional lookout point between the two main areas of the biotope. The layers of the black flysch to the west run sub-parallel to the coastline. Its erosion is therfore uniform and produces a straight coastal structure. The lime and sandy flysch to the east is perpendicular to the cliffs. This causes differential erosion and produces a more irregular coastal structure with headlands and small protected coves.

Rocky coastal platform of Sakoneta


The Sakoneta cove boasts one of the fines flysch formations of the rocky coastal platform between Deba and Zumaia. On its cliffs, the strata, which were originally horizontal are now in a vertical position. This is due to the internal movements of the earth caused 40 million years ago during the Alpine orogeny.


The San Sebastian hermitage of Elorriaga


The San Sebastian hermitage was an important enclave on the Coastal Route of Santiago. It is mentioned in 1625 by Lope de Isasti, who dates it back to the 10th-11th centuries. According to Aldazabal, it would date back to before the church of Itziar. Inside this simple hermitage, we can see the outstanding Romanesque baptismal font, also the image of the Virgin Mary (13th-14th centuries) and two small carvings of San Roke and San Sebastian.


Much more remote and hidden than Zumaia’s other beaches and much lesser known, this beautiful spot has little sand and its rocks are submerged under the sea every time the tide comes in. Due to its great beauty, however, it is nevertheless well worth a visit, especially in summer as the sun goes down over distant Matxitxako.

Itzurun beach

Opening directly out into the Bay of Biscay, under the watchful eye of the chapel dedicated to Saint Elmo, the patron saint of sailors, and enveloped in a spectacular series of vertical strata, this beach has been awarded by the certificate ISO 14001 and its dark sands offer stunning views over the whole of the Bizkaia coast, all the way to Matxitxako.

Technical brochure

  1. We start off on the route by the side of the Zumaia Town Hall (0 m). Walking between the narrow streets, we come to the parish church and, after descending some steps, we will find ourselves beside San Telmo Street. As we climb this street, we head towards the hermitage of the same name, situated on the cliffs of the Itzurun beach (800 m).
  2. After admiring the beauty of the cliffs, we begin a gentle descent until we almost reach the seashore. From here, we begin to climb a narrow path which leads us into a small valley. The climb ends when we reach the road that comes from Zumaia and which will take us to the nearby farmhouses, Andika Zahar and Andika Berri (2.100 m).
  3. From these farmhouses we will walk for a short time along the tarmac road until we turn to the right along the dirt path that takes us to the small hillock called Etarte. The path takes us up to Galarretako Zabala, in the district of Elorriaga, where there is a leisure area with tables and benches. In a few minutes, we will find ourselves in the centre of the district of Elorriaga, where we can stop to visit the San Sebastian hermitage (4.400 m).
  4. After leaving behind the district of Elorriaga, the signposts take us towards a dell near to the Txakotegain and Sorazumendi area. We then go down towards the Arantza Goikoa farmhouse and later to  Arantza Bekoa. From here, tha path goes down practically all the way to the coastline. After crossing the small channel of water at Errotaberri, we reach Sakoneta (7.700 m).
  5. From Sakoneta we begin to climb up to the farmhouse of the same name. To our right, below, we can see the Sakoneta and Mendata coves. In front of that, we can see the east face of Punta Mendata, more popularly known as Aitzuri. We descend towards the railway lines but before arriving, we pass over a tunnel and head towards the Mendata farmhouse (8.600 m).
  6. As we make our way along the path, parallel to the coastal strip, we begin to see the west face of the imposing stone mass known as Aitzuri. We start our way up towards the district of Itxaspe, until we reach the proximities of the campsite of the same name (10.800 m).
  7. From Itxaspe, we go down the track that crosses the area known as Atalaia and later Aitzuriaurre, and this takes us to the lowest point  of the small valley of Arronamendi.  Having reached this point, we then begin to climb up to the N-634 road in the proximitites of the panoramic vantage point of "La Salve". We cross the wooden walkway and take the path up to the hermitage of Santa Katalina (12.100 m).
  8. After resting and admiring the breathtaking panoramic views that the area affords us, we take tha path which, after crossing the fields, leads us to the Etxeberri and Iparragirre farmhouses. It is forbidden to descend the path close to the cliff as it is closed and very dangerous. Once we pass the farmhouses, we carry straight on along the signposted path with red and white marks of the GR. This goes down until it comes out onto a cement track next to the hermitage of San Roke. From this point, in a few minutes down a steep slope, we find ourselves in the old quarter of Deba (14.000 m).