One of the most respected and feared stages on the entire Norte, crossing the mountainous interior from Gipuzkoa into Bizkaia with over 2,000 metres of climbing and almost no settlements along the way. Spanish guides recommend doing this stage in company due to its isolation and difficulty.

The Collado de Arno, at the highest point of the Jacobean route in the Basque Country, marks the provincial border between Gipuzkoa and Bizkaia. The first 5 kilometres pass the chapel of Calvario and the Izarbide hostel. The only bar en route is at Olatz (uncertain hours, usually weekends and August only), so carrying food and water from Deba is essential. The terrain is steep and forested, with intricate paths requiring careful navigation.

Markina-Xemein is a traditional Basque market town known for its pelota traditions. The hexagonal Ermita de San Miguel de Arretxinaga (18th century) is built around three enormous natural boulders that balance against each other, forming a natural chapel. The Convent of the Carmelite Fathers houses a pilgrim hostel.