GR20 at a glance
- Distance: approx. 180 km
- Time needed: 15 stages (10–12 for strong walkers)
- Total ascent: approx. 12,000 m total ascent
- Start / finish: Calenzana to Conca (north to south)
- Season: Mid-June to late September
- Accommodation: PNRC refuges, bivouac tents and a few hotels
- Difficulty: Very strenuous, with scrambling and exposure
Stage by stage
- Calenzana to Ortu di u Piobbu — 12 km and 1,500 m of climbing on day one.
- Cirque de la Solitude / Monte Cinto variant — The old chained descent is closed; the route now goes via Monte Cinto's flank.
- Petra Piana to Onda — The Manganu and Rotondo section — the alpine heart of the trail.
- Vizzavona — The midpoint and the usual split for people walking only half.
- Vizzavona to Conca — Southern half: longer stages, forest, pools and easier ground.
North or south, or both
Vizzavona splits the trail. The northern half from Calenzana carries the reputation: granite slabs, hands-on scrambling, big daily ascents and genuine exposure. The southern half is still hard walking but on friendlier terrain with more shade and swimming.
Walkers short of time or confidence do the south first and come back for the north.
Heat, water and refuges
Corsica in July and August is hot and the trail runs high and dry. Early starts are not optional. Refuges are run by the Parc naturel régional de Corse, must be booked online in advance in the main season, and sell basic food — but they are small, so a bivouac plan is a sensible backup.
What ends people's GR20
Foot damage and heat, far more often than the scrambling. Fifteen consecutive days on sharp granite in high temperatures is a bigger ask than any single stage, and most people who bail do so in the first four days of the northern section.
Do you need a certified guide on the GR20?
The GR20 is waymarked and legally walkable alone, but the hands-on sections, the heat and the sustained load make a guided departure genuinely useful — especially for a first alpine-grade long trail. Group sizes are small and refuge beds are pre-booked.
GR20 questions
How hard is the GR20?
It is the hardest waymarked long trail in Europe: 15 stages, roughly 12,000 m of ascent, with scrambling, exposure and heat. Prior multi-day mountain experience is strongly advised.
Do you need climbing experience for the GR20?
No rope work is required, but you must be comfortable using your hands on rock and walking above drops. The Cirque de la Solitude chains are no longer part of the route.
How long does the GR20 take?
Fifteen days on the standard stage plan. Fit walkers combine stages and finish in 10 to 12.
When is the best time to walk the GR20?
Mid-June to late September. June can still hold snow on the northern cols; September gives cooler days and quieter refuges.