The walk goes through the valley of the Errota Berri towards the coast. Here you follow the coastal path in the Sakoneta nature reserve, which is part of the Costa Vasca Geopark, a protected area famous for its impressive flysch formations. This geological phenomenon shows millions of years of history in successive layers of rock. These rock formations were created by sedimentary deposits and erosion, leaving spectacular cliffs and patterns in the rocks visible. At the viewpoint above Sakoneta beach, you can see the irregular shapes of the flysch formations very well at low tide. The route goes to the Portutxiki viewpoint, from where you have a fantastic view of the cliffs and the sea. You return to the starting point via the same route.