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Guide updated on November 9, 2026

How to train for the GR20: fitness level and training plan

Is the GR20 right for you? How hard it really is, the fitness you need, a 10-week training plan and tips to avoid injury and having to give up.

With around 180 km and more than 11,000 m of elevation gain over often rocky terrain, the GR20 has a reputation as the toughest waymarked trek in Europe. It requires no mountaineering skills, but it does call for proper preparation.

What makes the GR20 hard

  • The terrain: boulder fields, slabs, big rocks to clamber over and sections equipped with chains, especially in the north.
  • The ascent and descent: climbs and descents of more than 1,000 m in one go.
  • The heat and the lack of water on some stages.
  • The cumulative effort: 13 to 16 days with no real rest.

10-week training plan

WeeksGoalExample
1–3Base fitness3 sessions a week (brisk walking, jogging, cycling) + 1 hike of 4 hours
4–6Elevation gain1 weekly hike of 6 hours with 1,000 m of ascent and an 8 kg pack
7–8Back-to-back days2–3 consecutive days of 6–8 hours, full pack, rocky terrain if possible
9Test runA long weekend of multi-day hiking in real conditions
10RecoveryShort outings: arrive in Calenzana well rested

Strength training (thighs, calves, core) and balance work on uneven ground greatly reduce the risk of sprains.

Adapting the GR20 to your level

  • Start with one half: the GR20 South is slightly less technical.
  • Choose the official 16-day schedule rather than a speeded-up program.
  • Keep your pack as light as possible and use poles (where they are allowed).
  • Build in buffer days for bad weather or a painful knee.

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