From Boí along the road to the ski resort up to the bridge that crosses the Sant Martí River, shortly after leaving behind Taüll and Pla de l’Ermita. Without crossing the road bridge, take the trail that goes up the Sant Martí River. Shortly after, start ascending along the trail that leads to Boïga de Sala, where there is a sign indicating the way to lakes Pessó. From there on the trail becomes very steep, as it climbs following the ravine of Pessó up to the first lake. Around half an hour later you will get to the end of the route, the greater Lake Pessó, 32 meters deep.