GR 11 (Spain)

The Senda Pirenaica traverses the Spanish side of the Pyrenees, running some 840 km from Cap de Higuer on the Bay of Biscay to Cap de Creus on the Mediterranean. Waymarked in red and white as the GR 11, it climbs through roughly 45,000 metres of ascent and takes strong walkers about six to seven weeks.

It runs higher and wilder than its French counterpart, threading the great granite amphitheatres of Aragon — Ordesa, the Aigüestortes lakes, the Aneto massif — and the remote valleys of Navarre and Catalonia. Long stretches cross uninhabited high country, with passes above 2,500 metres and the largest glaciers of the range in view.

This is a committing mountain trek. Several stages are long and exposed, water can be scarce, and snow lingers on the cols; navigation skill helps where waymarks fade. Refugios and valley villages provide beds and resupply, but gaps between them sometimes force a tent or an early start. No permit is required, though some national parks restrict wild camping.

The trail was pieced together in the 1980s from herders' and hunters' paths, completing a Spanish counterpart to the French GR 10. The dependable season is July to mid-September, once the high snow has melted; even then, afternoon storms are common, so early starts and flexible planning pay off across the higher central sections.