(0h00min; 0 kms) Refugio de Baiau o Josep María Montfort (2.517m).Walk down to Estany de Baiau lake and walk around it on the left, until you stand below Pico de Baiau peak, ignoring a path that climbs up to Collada dels Estanys Forcats. The path heads up through boulders, crosses a creek where you can fill up with water, and continues on a steep climb. Crampons may be obligatory in early summer.

(1h00min; 1,4 kms) Port de Baiau (2.757m). You are entering Andorra. The Pyrenees trail heads south down into the valley.

(1h20min; 2,1 kms) Estany Negre (2.640m). Walk around it on the left and keep walking downhill to the Basses d'Estany Negre which you also skirt on the left-hand side. The valley eventually opens out into the main valley of Coma Pedrosa. The path descends quickly, along the valley floor, passing the crossing to Coma Pedrosa mountain refuge, before reaching the...

(2h30min; 4,6 kms) Collet de Coma Pedrosa (2.224m). From this point the path descends decisively. At about 1,750m altitude, you join a wider path that converges with the GR11-1 variant and the Gran Recorrido GRP trails (Andorra circular walk) and GRT (3 Nations). A panel welcomes you to the Parc Natural Comunal de les Valls del Comapedrosa. Continue downhill, past a deposit, until you reach the first buildings of Arinsal. Cross a road tunnel, and on the other side you will find a tourist information point. Follow the road towards the centre of the village.

(4h15min; 9,5 kms) Arinsal (1.480m). At a roundabout in the centre, there is a road leading to Mas Ribafeta. Follow this road until, after a couple of hairpin bends, on a wide bend on the right, appears a very steep path that climbs without respite up to the...

(5h30min; 12,2 kms) Coll de les Cases (1.954m). The walk down the other side, through pine woodland, is also very steep, and soon brings you to...

(6h25min; 14,9 kms) Arans (1.370m).