GR20: Trail Thoughts

Beginning Note

As I was preparing for one of my expeditions last year, reading a guidebook, I came across a phrase that particularly resonated with me (paraphrasing): “The author doesn’t provide a list of equipment needed for those who choose to conquer this trail by sleeping outside the refugees, because if someone decides to do that, it means they should already know what they’re doing and what to bring.” In line with this philosophy, this post is not a guide or a list of things to pack. You can find those in many other places. Instead, it’s a loose collection of observations gleaned while traversing the trail, heard in conversations with fellow hikers, and read between the lines of guidebooks. I don’t intend to state the obvious about mountain trips, like “start early to avoid the heat, trail crowds, and catch the sunrise.” No. GR20 is a trail cutting through Corsica roughly from north to south, just under 200km long, nominally spread over 16 days and accumulating over 12,000m of elevation gain along the way. So, if you’re considering tackling this trail, start with thorough research, and buy a guidebook. And if you’re curious about things not mentioned in it, read this post.

Visualization based on my journey along with a selection of favorite photos. Click the link to see the photo gallery separately, a 2D map, and a link to the 3D trail.

The Best, the Hardest, the Most Popular

The GR20 is considered the most beautiful, the most challenging, and the most popular of all GR routes. While the first two attributes are subjective, the third is both measurable and undeniable — estimates suggest that between 20,000 to 30,000 people tackle the trail each year! This has several significant implications that it’s essential to be aware of:

• You’ll come across a plethora of materials and opinions, ranging from people emphasizing how challenging the trail is and how it transforms lives, to those boasting about completing it in seven days or running it in three (the current running record is just over 30 hours). When seeking information, be prepared to encounter opinions from “weekend tourists” creating drama and from “hardcores” downplaying certain risks. So, don’t be alarmed when another article about GR20 has a title like ‘Europe’s Toughest Trail! How I Barely Escaped with My Life!’ and don’t underestimate the trail when someone says it’s easy after crawling through it or running it in flip-flops — truth, as usual, lies in the middle.
• A significant portion of people embarking on the trail is unprepared — physically, equipment-wise, and mentally. I’ve encountered signs saying “snow” on some trail markers (which seems somewhat absurd at first glance, akin to saying “caution, it’s raining”). However, since ‘every sign tells a story,’ and the signs are always in English, it suggests that tourists often don’t realize that there might be snow on some sections, even in the summer. Don’t be one of them; do your homework.

Warning sign about snow on the trail.

• Crowded Trail and Shelters: The trail is crowded, as are the refuges. I traveled in mid-October, well outside the peak season, and still encountered several people daily — both on the trail and in the refuges at day’s end. It’s worth mentioning that the refuges are open but unstaffed outside the season (you can sleep, but can’t buy anything, and there’s a water source somewhere outside). If you plan to do this route during the season, forget about experiencing the solitude of a mountain expedition. And be prepared for queues at the refuges.

Venturing off-season means carrying your own food — my one-week supply for the journey.

You can also rely on foraging along the way. Just remember: all mushrooms are edible, but some only once.

• With such traffic on the trail, even if certain behaviors are marginal, there is a much greater chance of their occurrence. For example, if one in a thousand people lacks a strong enough moral compass to venture far enough into a secluded place when nature calls, it gives us dozens of people each year leaving ‘landmines’ topped with toilet paper right by the trail — something dishearteningly common to observe. If one in a thousand people is determined to ignore weather conditions and embark on the journey regardless, even with only a 10% chance of an accident, it results in several cases of rescue intervention or even deaths annually.

In any case, having some ‘mountain savvy’ or awareness that:

• Yes, it can be cold.
• Yes, it can be hot.
• Even in summer, there might be snow at higher altitudes.
• It can be so steep that you may need to use your hands at times.
• There might be little to no phone signal most of the time.
• There may be few places to buy anything.
• If available, choices might be limited.
• Access to electricity will also be occasional.
• You’ll have to wash in a cold river; if there’s a shower, it might not be much warmer.
• You’ll need to pitch your tent on hard, rocky ground.
• You’ll need to carry several liters of water, and so on,

is very helpful. If these aspects are not obvious to someone embarking on such a trail, disappointment may be inevitable. If this list scares you, it might not be the expedition for you. If it’s obvious to you, you’ll likely enjoy it. :)

Disposable boots

According to my guidebook, the GR20 is one of the best-marked trails in Europe. This is due not only to the trail’s popularity — locals derive significant income from tourism and therefore maintain the trails meticulously — but also to its unique characteristics. When I first heard about the GR20 from a companion during one of my previous mountain expeditions, he mentioned two things:

1. Be careful, as if you leave food in the tent, wild boars and foxes will get to it — they’ll eat the food and puncture the tent.
2. You’ll need to discard your shoes.

Foxes and wild boars — understandably, with such crowds passing through, it’s no wonder that they get accustomed and learn to take advantage of tourists. Fortunately, I didn’t have the chance to experience this personally. Only on the last night, after completing the trail, I decided to take a risk and leave my unstrapped shoes outside. However, the next morning, I found one of them a few meters away. I don’t know what took it, but whatever it was, it probably died after sniffing it. Nevertheless, I’ve heard many stories from people in shelters about animals taking their unattended food or clothing. But does this mean that your shoes won’t serve you anymore after the GR20? Not only for these reasons.

This guy is eyeing my shoes.

The main threat to our footwear will be Corsica itself — a large piece of granite protruding from the sea. The rocky nature of the terrain makes the path difficult and requires attention. During any long-distance trail, we inevitably encounter various types of paths — from asphalt when passing through mountain villages, through gravel-packed forest roads, to beaten muddy paths through rocky ‘stairs’ and scrambling over rocks. During the GR20, the center of gravity on this scale is decidedly shifted towards the latter. Throughout the entire route, we may walk a total of perhaps a few kilometers on asphalt, maybe a dozen through forest roads, and the majority is simply rocks. Often, large rocks where we walk for several meters on a single piece of stone. Or on a stony slope that looks the same everywhere, and we have to carefully look for the path because it doesn’t stand out in any clear way. Climbing sections are also common, where we have to grab rocks or chains if they are available.

Examples of typical rocky sections on the GR20 — try to spot the markings and deduce exactly where to go.

A section requiring climbing (or squeezing through).

Yes, this photo is practically vertical — a trail fragment with auxiliary chains.

A path passing through a rock, with roots breaking through.

A section of the path to overcome on a solid piece of rock.

Yes, there are also sections with a more forgiving surface.

There are also places where both the quality of the path and the level of marking prevent you from getting lost.

Even at night, due to the applied paint, the markings can be relatively easily followed in the light of a headlamp.

Sometimes visibility is worse… Walking at night, in fog, with visibility limited to a few meters, I sometimes wonder if I haven’t already passed the shelter without noticing it.

Generally, I consider it a significant advantage of the trail — one doesn’t venture into the wilderness to walk on asphalt. However, one must be prepared for the fact that the assumption ‘I’ll cover N kilometers a day’ may slightly miss the mark in reality. Distances in kilometers and elevation in meters don’t tell the whole story here. I often found myself in a situation where, with only 1–2 km to cover and perhaps 200–300 m downhill in that distance, it took me over an hour (!) because I had to constantly watch my steps and consider where to place each subsequent foot. There is a huge difference between a stable surface where, even uphill, we can maintain a steady pace, and irregular rocks where we have to watch our step instead of enjoying the views.

For route planning, I recommend respecting generally accepted travel times between specific points, which are provided either on signposts or in guidebooks. The travel time will, of course, vary depending on the weather, our fitness, and the weight of our backpack. There is no other method than empirically determining how our pace compares to the ‘textbook’ pace — measure how much time it took to cover each section. By averaging, we can ascertain whether we are moving on average faster, slower, or in line with the provided times. Then we can estimate how much time we need to cover a section planned for a particular day. Also, keep in mind that the given times do not include breaks for waiting for a cow to pose for a photo or replenishing the level of gummy bears in the bloodstream.

Corsican fauna posing for photos. (Some flora along the way as well. Mainly bacterial on sticks.)

And what about my shoes? Yes, I was prepared for them to have a tough experience. So, I decided not to buy new ones but to take the ones that had served me for over a year and wear them out. They looked good, so before the trip, I glued all the beginnings of material peeling, achieving IP56 at least. I also brought glue with me and glued them halfway through the trail. They held up just so. On the last day, the right shoe only held at the front on the tip, and I had to be careful when descending not to put my full weight on it. The tread on the sole is now just a distant memory of the shoemaking craft. I highly recommend knowing your shoes well before embarking on such an adventure.

The shoe after a week of Corsican treatment.

Corsican Dream — or where to sleep

Setting up a camp is officially prohibited throughout the entire GR20. Regardless of whether it’s justified or not, and whether we intend to obey this law, the fact is that for most of the trail, there is simply no physical possibility of pitching a tent — as I mentioned before, rocks are everywhere, and even the most determined advocates of sleeping on the floor and acupressure mats may not manage. Even at refuges, which are usually located in the best possible places for this purpose, platforms specially built for pitching tents are used. In a few places along the trail, you may come across improvised camping areas. Of course, sleeping there is officially illegal, and reportedly, during the season, authorities may check whether the rule is being followed. I have mixed feelings about this — I mean, if someone sets up somewhere for the night and cleans up after themselves, nature won’t suffer much more than from a regular passage along the trail. On the other hand, considering the popularity of the trail, if everyone slept wherever they wanted, those few flowers that managed to grow between the rocks might indeed be trampled beyond recognition. However, they probably wouldn’t complain about the lack of fertilizer.

Reminders of the camping prohibition, encountered on the trail.

Someone who didn’t pay much attention to this prohibition.

Examples of small places for potential emergency tent pitching (or shelter from a storm).

Platforms at refuges providing a flat surface.

As for tents, that’s the story. However, yes, you can also sleep in refutes. But for the brave souls who decide to stay in crowded shelters during the season, be prepared for the following:

• You need to reserve them in advance, which significantly complicates route planning if, for example, you get stuck somewhere due to bad weather.
• In most refuges, there is no hot water, toilet paper, and sometimes no toilets at all.
• Sanitary conditions in shelters are far from ideal. The common problem? Bugs. On GR20 forums, you can find instructions on how to buy a few meters of mosquito netting, a zipper, and sew a cover into which you can enter with your sleeping bag to avoid bug bites. If this fact doesn’t convince you that a tent or an off-season trip is a better option, I don’t know what will. Also, don’t be surprised that if you decide to stay in a hotel halfway or at the end of the trail, you will be asked to leave your backpacks outside if you slept in a shelter earlier — due to the risk of transferring bugs.

Shelter interiors off-season — empty and bug-free. Also staff-, hot water- and food-free.

Famous Corsican weather

Another characteristic feature of Corsica is powerful storms. Even rainfall alone can be dangerous. Steep rocky passages can turn into raging streams, carrying the risk not only of slipping on wet rocks but also the threat of being washed off the trail! It is often necessary to wait out the blocked section in open terrain, which in the case of rain and wind is at least uncomfortable; during a full storm, it is downright dangerous. I even heard about a case a few weeks earlier when a person died because they were washed away with their car while driving on the road. Therefore, it’s essential to check the weather forecast as often as possible. During the season, refuge staff have the necessary information. Off-season, if we couldn’t check the weather that morning (don’t count on a daily dose of the internet), it’s a good idea to ask fellow hikers about it. You can also learn interesting things this way. One day, I met a man who, when asked when he last checked the weather, replied something like, “Yesterday, I talked to some old guy who, after staring at the sky for a few minutes, said, ‘Hmm, the clouds passed over the ridge, we have three days of rain-free weather,’ he looked like he knew what he was talking about, so I believe him.” It rained a bit in the coming days, but not terribly, so you could say the man had his measuring equipment properly calibrated.

Found in the depths of the internet: https://gr20corsica.wordpress.com/about/

Sample Corsican storms.

Changes, Changes… But for the Better?

Another non-obvious thing is that the GR20 (like other trails) is not set in stone. (At least metaphorically, literally it’s sometimes is.) Trails are modified every year — landslides, property boundaries, infrastructure adjustments, opening and closing of variants — all these contribute to gradually changing the course of the trail.

One of the most famous examples is Cirque de la Solitude — a legendary section closed in 2015 after seven tourists died attempting it in unfavorable weather conditions. This section was considered the most challenging, with the number of auxiliary metal elements making it resemble via ferrata more than a trekking trail. After the mentioned incident, the section was officially closed and is considered impassable. However, some adventurers still attempt it, and there are videos on YouTube showing the current state of the trail. Of course, local guides are also willing to take tourists there for a fee. It’s essential to note that the fame of the GR20 as the “hardest trail” was built when Cirque de la Solitude was an integral part of it, and the current situation is not as dramatic.

Another well-known example is sections 13 and 14 between Refuge d’Usciolu and Refuge d’Asinau, replacing the previous single-day section connecting the two shelters. The official explanation I found is that the “previous section was too long and tedious for tourists.” Therefore, the official trail was diverted around and split into two days. The old option remained but was marked as an alternative variant. In the guidebook (from 2022), I even found a note that the sign at the intersection showing the start of the variant is often removed, destroyed, or smeared to ‘encourage’ people to choose the longer route. The reason for such ‘encouragement’ and the designation of a new route is to direct tourists to the refuge and the cheese shop. When I hiked the trail (in October 2023), I encountered a sign explicitly stating that the variant was closed. Still, despite that, I decided to take it (the added pen-written note in French somehow spoke to me with a certain homely confidence), and I noticed that all trail markings along the way had been smeared.

Find the difference between these pictures. Left: Sign: Danger explosion zone. Note: Smoke without fear, will not blow up. Right: Variant closed. Note: It’s OK. I passed it without a problem.

Blurred trail symbol on a tree.

Blurred trail symbols on stones (harder to spot).

I didn’t notice anything along the way that could suggest the trail might have been impassable in the last year due to an event like a landslide. I also don’t think it’s about nature conservation because, generally in French mountains, if a trail is closed, the reason is clearly stated. Asking people about it, I mainly received answers like “I don’t know what’s going on, but I talked to people yesterday who did the trail in the opposite direction and said there was no problem.” The variant itself is very picturesque and goes through one of the few potentially flat valleys allowing for tent camping.

Fragments of the ‘forbidden’ section.

Dismantled footbridge. More of a result than a cause of closing the section.

Another variable element of the trail, whose variability may not be so obvious, is the refuges(!). One would think that a refuge stands and will stand… unfortunately, not in Corsica. On the first day of the trip, I met a few compatriots who had done this trail not for the first time, from whom I learned some interesting facts. This time, they planned to do only the northern half of the trail because in the south, “they get annoyed by how they changed this trail — instead of leading it through some interesting features, it leads you around some bushes so you can buy cheese at the shepherd’s hut. This refuge at the end of the first day — it’s gone. It burned down, of course. Incidentally, a refuge will accidentally burn down, and then a hotel will open a few kilometers away, and the trail will lead that way.” My temporary travel companion clearly suggested that refuges don’t accidentally burn down — they are destroyed so that they can be replaced with more profitable infrastructure. As I mentioned earlier, traveling in 2023, I encountered (or rather didn’t encounter) two refuges that burned down earlier that year! The second one (Refuge d’Asinau) was rebuilt in 2018 after a fire. And yes, this is the refuge at the end of the aforementioned 14th stage, which makes completing the old variant 13+14 even more troublesome. While it doesn’t surprise me that a refuge could burn down due to lightning strike or heat (using an open fire is generally prohibited on the trail), the frequency at which refuges on the GR20 burn down seems a bit suspicious. In any case, when planning a trip, I advise checking if all the refuges where we plan to stay still exist.

The current (as of October 2023) division of the trail:

Yes, it is divided into 16 stages… As I mentioned, kilometers and elevation gain are a weak measure. For example, on the fourth day (the highest stage, passing near Monte Cinto), it predicts over 8 hours for 10 km, which means a pace just above 1 km/h. And indeed, that’s what an “average, fit hiker” should expect. It is, however, the only stage that long (in terms of time). There are quite a few stages lasting about 5 hours, and the average is 6 hours… Yes, only 6 hours to cover in a whole day.

The good news is the availability of numerous variants — many places allow shortening the trail and going through higher parts with better views, or vice versa — overlaying the route and going through lower terrain in case we are unsure of the weather conditions, and there are no views due to clouds.

Of course, you can go even with clouds.

However, it’s excellent if it’s a choice and not a pushed necessity. Unfortunately, looking at all these changes, the situations and conditions I could observe on the trail, after talking to people along the way, and reading allusions in guidebooks and articles, I find it hard to shake off the impression that the trail is gradually becoming more simplified (harder sections replaced by easier ones) and directing tourists to refuges, shepherd’s huts, and hotels so they leave their money there. It seems that the trail is designed so that the tourist is on the trail for as many days as possible, sleeping god forbid in wilderness, where they wouldn’t have to pay, ideally walking only a few hours a day, spending the rest of the time sitting and spending money in a refuge, or ideally a hotel, because the refuge burned down again…

I am far from seeking some grand conspiracy here. I also don’t want to say that these changes are necessarily a wrong direction if it’s just an alternative option. For many people, these 16 days are exactly as much as their fitness allows. Going down to shepherd’s huts or hotels to try local products also has its undeniable charm, and I sometimes do it if something is open. Closing sections that are genuinely dangerous and pose a constant threat also makes sense. Similarly, taking the trail slowly, in 16 days or even longer, walking just around 5 hours a day and staying in the best conditions at night, is also not something worse. It’s great that there is such an option, especially for older people who have enough courage and vigor to take on such a trail, or parents with children who want to instill a love for the mountains from a young age.

Typical (at least that’s what I’m told) Corsican food in a hotel in Vizzavona, where I stopped halfway through the trail. Why not — I do it sometimes too.

However, I am decidedly against depriving people of the choice and suggesting or even spreading misinformation that some part is impassable, and the designated route is the only correct one, and staying in a particular hotel is the only option. Out of curiosity, I will observe whether this trend continues and how the trail will run in the next few decades. In the meantime, I encourage anyone willing to hike this trail to thoroughly familiarize themselves with its course, be aware that often alternative variants can be chosen (not only those mentioned as official variants, there is often the possibility of shortening the trail by another path if, for example, you do not plan to stay overnight in a particular place), that shelters and sleeping spots are not only at the ends of the mentioned stages but often also during them, and some sections are short and easy. So, there is a very real possibility of doing like 1.5–2 section every day, without pushing too hard, if, of course, the fitness allows. I believe it is better to assume more time buffer for bad weather and time to get to and from the ends of the trail (Corsica is a relatively small and sparsely populated island, and public transport is practically nonexistent, making getting from the airport or port to the trail an equally challenging logistical task) than assuming that the trail itself will actually take us 16 days; you can comfortably aim for closer to 10 days for a fit hiker.

Conclusions

• The timing is crucial when you embark on a journey.
• Setting out early, be prepared for snow.
• Setting out early or late, be prepared for closed shops.
• Setting out in the season, be prepared for crowds.
• Be prepared for difficult terrain — take care of good boots.
• Beware of wild animals — do not leave things outside the tent at night or unattended in the tent.
• Check weather forecasts whenever possible.
• Plan your route carefully — analyze where you plan to sleep each day (or be aware of your options).
• You can probably carve out a more interesting and faster route if you deviate from the suggested 16-day division.
• Use the most up-to-date data about the trail — it is modified every few years (for better or worse).
• Check current information about refuges where you plan to stay — there is a significant risk that some of them have burned down this year.

No one expected the Spanish Inq… I mean the French Foreign Legion.

Verdict

The council will decide your fate.

In summary: The most crowded? Definitely. But certainly not the most boring! The most beautiful? Undoubtedly, it’s a beautiful route. Although it didn’t become my favorite, I must admit that, being relatively short, it encompasses many incredible views and places — probably the maximum you can squeeze into one or two weeks. It guarantees a full range of experiences regardless of the season and time — each has its uniqueness.

But is it the most difficult? I consider the route relatively challenging but in the sense of being ‘demanding,’ not in the sense of being ‘dangerous’ — as long as it is done wisely, with appropriate equipment, and in good weather conditions. It can be done as the beginning of a long-distance trekking adventure, but I do not recommend it as the beginning of a mountain adventure in general.

I also met people doing this route with children or dogs — if you are sure they can handle it, and you can carry your child or dog for some distance if needed (for dogs, in some places, it’s rather a necessity, or you have to bypass certain sections with variants), then I don’t see additional contraindications. And if you insist on wanting to do Cirque de la Solitude despite the danger and legendary difficulty… let me know; I’d be happy to join when I do this route again