The climb begins from Les Forges d'Abel, in the french valley of Aspe and about 40 km north from Jaca. The closest spanish province capitals are Pamplona and Huesca. The trip from Pamplona should be done by road N240 (road signs "Huesca") until the small village of Puente la Reina. Right after crossing Puente, on the other side of the Aragón river turn left to follow the signs to Jaca. From the city of Huesca it's all the way along road N330, crossing the Monrepós mountain pass to reach the city of Sabiñánigo and turning left there to get to Jaca in twenty kilometers more. There will be only fourteen kilometers left to go north, and right after crossing the village of Villanúa and the road tunnel after it you shall be in sight of Canfranc. Follow the road towards Canfranc Estación, the railroad station quarter of Canfranc. Cross the road tunnel under the Pyrenees (entrance to the tunnel placed before the entrance to Canfranc Estación) and follow it to the french side. Just after emerging from the tunnel you will find a crossing left (west) signposted "Les Forges d'Abel". Take it and keep driving for some four additional kilometers to reach the parking area of Espelunguère (also signposted as such by the authorities of the French National Park of the Pyrenees. That's the spot to leave the car at. The road goes on, but this is the best possible place to park in and allows for a visit to the nearby cascade.
In order to get to Espelunguère from France, start from the town of Oloron Ste-Marie and follow the road to the spanish border, south, all along the Vallée d'Aspe. Turn right just before the french entrance to the Somport road tunnel and follow the previous instructions.
NEAREST MAJOR AIRPORTS:
Zaragoza / Barcelona (323 km) in Spain, Pau or Biarritz in France
The nearest rail stations in Spain are the ones at Sabiñánigo and Jaca. Additional transport will therefore be required from that point on.
Valle de los Sarrios and East face of Bisaurín
This is a long, long climb. It means having to climb 1600 meters (about 2000 meters if you consider the accumulated altitude gain) from the car to the summit and back again, therefore it might be somewhere around 10 hours walk.
First step is to walk along the Vallée d'Espelunguere by a good dirt road until you get to the Electric Plant of Estaens. That's the point where you shall turn south by the path leading to Pas de l'Echelle. At first you shall climb through forest areas, but the final climb before the Ibón (lake) de Estanés is a rocky barrier that some climbers might find a little bit aerial. Not hard, not difficult, but it is NOT advisable to undertake this effort before sunrise.
After Pas de l'Echelle (1775 meters) you shall find yourself at the Ibón de Estanés. Walk around the lake by its eastern shore, following a path marked by cairns, in search of the breach placed south of you. That breach is called "La Trinchera" and gives access to the hanging Valle de los Sarrios, a beautiful secluded valley going south at first and west afterwards. When the slope starts coming down, at the Puerto de Bernera (Bernera Col) you shall already be looking west and have Bisaurín in front of you. Keep walking west, but remember you do not have to reach the obvious Collado (col) de Secús. Shortly before the col you shall find a scree couloir going up and southwest (on your left), leading to the summit without any technical challenge but with the logical effort.
IF YOU GET TO THE COLLADO DE SECUS, getting to the summit shall still be possible but your only way up will be the north ridge of Bisaurín (technical climb, small difficulty)
An alternative route to reach the Ibón de Estanés
This information has been kindly incorporated by edouet:
When coming to Bisaurín from the french side of the border (from Oloron-Ste.Marie), following the old road to the Col du Somport (do not cross the new road tunnel to Spain), stop at the " Parking du Sansanet " (elevation: 1330m). After crossing the Gave d'Aspe, a one hour-walk on a good trail (about half of it goes through the forest) will lead you to the Ibón. No difficulty. This alternative makes the climb to Bisaurín a 1600m elevation hike, but from the Electric Plant of Estaens it is a 2000m accumulated altitude gain as , you have to go down 200m from the Circo de Olibon to the Llano Mistresas; these 200m need to be climbed on the way back.
No real needs apart from the logical ones imposed by the season. That means full equipment for the winter climbs, including warm clothing, gloves, crampons and ice axe.