Start the climb from the mountain hut of Linza. You will have to get there from Pamplona or Huesca, the biggest closer cities. Follow the road linking both of them (N-240) until the crossing of Venta Carrica. This is a crossing about (will check) sixty kilometers from Pamplona, where you can find a petrol station and the beginning of the road to Sigüés / Salvatierra de Esca / Roncal. Follow this road (NA-137) for thirty kilometers, until you get to Isaba. After Isaba keep going north (NA-1370) for three more kilometers and turn right on the crossing marked as (Zuriza /Ansó). This small road (NA-2000) will take you across the valley of Belabarce and to the camping area at Zuriza, under the Sierra de los Alanos. When you finish coming down from Belabarce (that will be some thirteen kilometers after Isaba), turn left for the camping area and drive around it until the end of the road. It is not in a very good state, so don't drive fast. You will see the dirt roads to Barranco de las Eras and Barranco de Gamueta to the right, but pay them no attention. Keep going on the main road until a final turn right, around a rocky hill, sets you on the small flat valley known as Plano de la Casa and the mountain hut of Linza.
Nearest railway stations
: Pamplona / Huesca
: Pamplona / Zaragoza
Start walking eastwards from the parking lot placed by the mountain hut. The route is a common one for Petrechema, Lapakiza and Mesa de los Tres Reyes up to the Collado de Linza. At first
you shall be walking over easy terrain, mainly grassy slopes and short areas of scree path. The trail is obvious and turns around two or three grassy hills by their southern side. It shall be 30 to 45 minutes before the path turns slightly north and gets you into a flat area placed under the slopes of Lapakiza de Linzola. This is the waypoint marked in maps as "Sobrante de Linza" or "Fuentes de Linza". There is a small stream coming down the place, offering water for emergencies, but beware: specially in summer season a number of cattle might be grazing around and turn it into a dubious quality water. It can also be absolutely dry by the end of the summer season.
Anyway, you have to cross the stream to its eastern side and keep following the path to start climbing the slopes in a north-east direction. At first it will be a little winding and take you to a spot placed under a small rocky cliff. Beginners might be impressed by this pass, but it's not really difficult: just a matter of about twenty meters long to be crossed horizontally. It falls a little bit southwards and occasionally can have loose scree, but after that there will be no more of the question. You will find yourselves in a kind of green terrasse leading eastwards (grossly) and slowly gaining altitude towards the Collado de Linza where you shall get in about twenty to thirty more minutes, that is one hour and a half after beginning the climb.
At this point
just look around. Mesa de los Tres Reyes and Budoguía are placed to the north and north-east. The path leading there crosses the col and keeps going north, around a grassy small hill. Follow it, paying no attention to the climbers going east towards Petrechema. There's a short descent (west-northwest) in full sight of Lapakiza. As the path turns north, look for a proper spot to turn left and face the final grassy slopes of the climb. The real summit is not easily seen from this area, but you will find it easily enough as it's marked by a small mailbox in the shape of a country house.
From the summit
Depends on the time of the year... Good boots and hiking poles should be enough for spring and autumn, but winter and spring (specially early spring!) climbs require good clothing, waterproof boots and (in some cases) even ice-axe and crampons.