Lac Blanc Walk in Chamonix: the Finest Balcony Over Mont-Blanc?

A mountain lake at 2,352 metres, sitting on the granite terraces of the Aiguilles Rouges. Opposite, the Aiguille Verte, the Drus and Mont-Blanc turn over in the water as soon as the wind drops. That picture is what draws walkers up to Lac Blanc, above Chamonix, every summer.

At Altimood we come up this side once or several times a season, by cable car as readily as by the ladders of Tré-le-Champ. Lac Blanc is not a secret, and that is precisely why the starting point matters: la Flégère, the col des Montets, Tré-le-Champ or the valley floor give you four quite different days out. Length, ascent, technical ground and crowds all change. The table below compares the four with their GPX trace, and the rest of the article deals with the real difficulty, the season, the regulations and the refuge.

Distances and times are there and back, or the full circuit, walking time excluding stops. The ascent figures are those of our GPX traces, downloadable under each route.

Is Lac Blanc the finest balcony over Mont-Blanc?

Strictly speaking, no, and we might as well get that out of the way. For taking in the massif as a whole, the Brévent (2,525 m) does the job better: higher, more front-on, a full 360°. It is the viewpoint most TMB walkers mention first. The Grand Balcon Nord and the Lacs Noirs have their supporters as well, and what you take away will depend chiefly on the light, the weather that day, the number of people on the path and the state of your legs.

What Lac Blanc has, and the Brévent does not, is the water: here the massif is both in front of you and in the lake. That mirror at 2,352 m is what makes it the most photographed viewpoint in the valley, and the reason is geographical first of all.

The lake faces due south, square on to the north side of the Mont-Blanc massif. From the shore the eye runs uninterrupted along the Aiguille du Chardonnet (3,824 m), the Aiguille d'Argentière (3,902 m), the Aiguille Verte (4,122 m) and the Drus (3,754 m) above the Mer de Glace, then the Grandes Jorasses (4,208 m) and, further right, the dome of Mont-Blanc (4,807 m). Between them, the glaciers of Le Tour, Argentière and Les Bossons run down towards the valley. On flat water, the whole lot doubles in the lake.

We talk about "Lac Blanc" in the singular, but there are in fact two basins: the lower one, 3 metres deep, and the upper one, 10 metres. The water is not white in the least, it is clear, and the name probably comes from the snow, which holds on the lake for a good part of the year and sometimes frees the north shore only in high summer. The few minutes' detour up to the top basin is worth taking: the same view of the massif, considerably fewer people on the bank at lunchtime. Early on, before the cable cars start, you may well meet ibex on the slabs and hear marmots whistling.

The 4 routes up to Lac Blanc

They all arrive at the same lake, but they are not asking the same of your legs. Here is how we separate them.

Via la Flégère: the shortest, with the cable car

The standard way up, and the easiest. You take the cable car from Les Praz de Chamonix (1,068 m) to the la Flégère station (1,877 m), then walk to the lake on a well-made path. The ascent takes 2 to 2 hrs 30, with a few rocky steps where a hand goes down, but nothing exposed: this is the version children can manage from about seven. Mild surprise as you leave the cabin, the path begins by dropping some thirty metres into the combe de Chavanne before the climbing proper starts.

The trace below covers the ascent only. There and back, allow 6.3 km and +525 m.

• Distance :↔ 3.1 km
• Dénivelé positif :↗ 493 m
• Dénivelé négatif :↘ 32 m

La Flégère cable car: fares and times

Free under 5, group rate from 20 people. Fares are in euros, and the pound has generally bought rather more than one of them in recent years, so the figures look slightly kinder in sterling than they read here. Check the rate before you commit to a budget. For summer 2026 the published times run from 11 July to 13 September: first cabin at 8.20am and last descent at 6pm until 30 August, then 8.35am and 5pm from 31 August to 13 September. Dates and fares shift from year to year, so check before you set off.

The detail that repays attention: a single is €19 and a return €25. Walking back down to Les Praz therefore saves you all of €6, in exchange for 800 metres of descent through your knees. The other way round, walking up and using the cabin only to get home costs the same, and it is often the better arrangement with tired children in tow.

To avoid repeating the same path, many walkers come down past the lacs des Chéserys. Beware the widely quoted 45 minutes: that is Lac Blanc to the lacs des Chéserys, not the return in full, which takes over two hours to la Flégère. And if you chose this way up on the strength of a promise that there was "nothing exposed", be aware that this descent includes steps and a short metal ladder. Nothing difficult, but you would rather not meet it as news.

The la Flégère car park, at Les Praz, charges in season.

The Index variant, for avoiding the crowd

From la Flégère, a chairlift goes up to the Index (2,401 m). From there the path traverses to the refuge along a balcony, near enough level, in around 1 hr 20. It costs more and the ascent becomes a rounding error. Last lift up to the Index around 5pm, last descent around 5.45pm in high season.

The trace below covers the traverse alone, from the top of the chairlift to the lake: 2.8 km, +130 m and -160 m. Double it if you return the same way, or drop onto the descent to la Flégère.

• Distance :↔ 2.8 km
• Dénivelé positif :↗ 133 m
• Dénivelé négatif :↘ 160 m

Via the col des Montets: the entirely on-foot ascent

To do without the lifts but without signing up for a huge day, the col des Montets (1,461 m) is a fair compromise. The path climbs through forest and then pasture, passes the lacs des Chéserys and reaches Lac Blanc in 3 to 3 hrs 30, for +965 m. It is quieter than the la Flégère route and more varied too, with that procession of high lakes one after another.

The trace below starts at Montroc-Le Planet station, on the Mont-Blanc Express, and loops back over the col des Montets: a car-free day of 12.7 km and +1,070 m, longer than the ascent from the pass itself but it disposes of the parking question. One thing to know before following it: it returns via the Tête aux Vents and the Aiguillette d'Argentière ladders. If you chose the col des Montets specifically to avoid those ladders, go back down your line of ascent.

• Distance :↔ 12.7 km
• Dénivelé positif :↗ 1073 m
• Dénivelé négatif :↘ 1074 m

From Argentière or Tré-le-Champ: the ladder path

This is the approach that gave the area its wild reputation. Above Argentière the path climbs towards the Aiguillette d'Argentière (1,893 m), then crosses a rock band by a series of metal ladders and cables. The sections are exposed but well equipped and call for no climbing technique: the hands are there to steady you. The drop is real all the same, and we are not all equal in front of it. Which way round you take the circuit is no small matter: a ladder goes up a good deal better than it comes down, and up is the way we take them with our groups.

That section between Tré-le-Champ and la Flégère is stage 10 of the Tour du Mont-Blanc, which we set out step by step in its own article: if you are preparing the TMB, the ladders are where that day is decided.

The trace below makes a circuit from Argentière station (1,246 m), which means you can come by train: 12.2 km and +1,200 m, ladders included. As drawn, it climbs by the Chéserys and returns via the Tête aux Vents and the ladders. To take them on the way up, walk it the other way round. By car, the Tré-le-Champ car park, higher up the pass road, removes the approach from the valley floor.

• Distance :↔ 12.2 km
• Dénivelé positif :↗ 1196 m
• Dénivelé négatif :↘ 1196 m

From Les Praz: the full version, no mechanical help

It is quite possible to do the lot on foot from the valley floor, at Les Praz (1,068 m). The first two hours climb through forest, shaded and cool, with no sight of the massif until you leave the trees. That is what the cable car skips, and it is also what makes the walking start bearable in high summer: in real heat those two hours under the larches pass a great deal better than the same ascent in open sun. Most walkers combine the climb on foot with a cable car descent, or the reverse. You want some reserve in the legs.

The trace below leaves from Les Praz station and loops by Lac Blanc: 19.4 km and close to +1,600 m, the biggest of the four days.

• Distance :↔ 19.4 km
• Dénivelé positif :↗ 1596 m
• Dénivelé négatif :↘ 1596 m

Getting there without a car

Here is the argument that tends to be forgotten: the Mont-Blanc Express serves Les Praz, Argentière and Montroc-Le Planet, which is one station per route. Three of the traces above start directly from a station (Argentière for the ladders, Montroc for the col des Montets, Les Praz for the full version), and the la Flégère cable car is a few minutes' walk from Les Praz station. Not one of the four starts obliges you to drive.

In July and August, when the valley car parks are full by 9am, the train is simply the easiest way to reach the start. It also lets you finish the day somewhere other than where you began: up via Tré-le-Champ and down to Les Praz through la Flégère, say, with no need to go back for a car.

Extending to the other lakes

Once you are up there, Lac Blanc is not the only basin about. The lacs des Chéserys, just below, can be taken in on the way back without adding much, and with fewer people. Push on a little and you reach the lac Cornu and the Lacs Noirs, or the small lac de Persévérance, which gives another angle on Lac Blanc. Walkers with the reserves for it can also cross to the Index by chairlift and drop down the la Flégère side.

Difficulty: it depends entirely on where you start

Lac Blanc does not have one grade, it has four. By la Flégère it is a family day: steady climbing, a few rocky steps, nothing exposed. By Tré-le-Champ you are in another register altogether, with the ladders and the ledge, ground that asks you to be comfortable with height.

If heights bother you but you still want the walking version, the ascent from the col des Montets avoids the exposed Aiguillette d'Argentière ladders, on one condition: come back down the way you went up. Done as a circuit, the return by the Tête aux Vents leads straight onto those ladders, and that is the line our trace takes. One further point worth knowing: none of these routes gets you out of the short ladder over the slabs between the Chéserys and the lake, which is common to every walking approach. It is brief and easy, but it is there, and it is as well to know before you set off with someone the drop unsettles. The only genuinely ladder-free option is the direct there-and-back from la Flégère. Whichever route you take, this is high mountain path, well waymarked but stony, where decent boots with ankle support and poles for the descent make the day.

When to do the Lac Blanc walk

The dependable window runs from late June to late October. Before mid-June the snow is still holding on the Aiguilles Rouges: patches cover the path above 2,000 m and the lake is often frozen, sometimes white with snow until the end of spring. At the other end, autumn walks very well once the cable car has stopped, so long as the snow has not returned: the refuge, for its part, gives its 2026 season as running to 1 November.

In June and early July the slopes are covered in flowering rhododendrons and the streams are full. In July and August the weather is at its steadiest, but this is also peak traffic: the association that runs the reserve counts 1,000 to 1,500 people a day at the lake in high summer. In September the low light and thinner crowds make for a calmer ascent. One date to note if you are after quiet: the week of the Ultra-Trail du Mont-Blanc, 24 to 30 August in 2026. The race's final climb goes over the Tête aux Vents and la Flégère, which is exactly the slope you descend from Tré-le-Champ, and most of the field passes through in the dark. The start is given at Chamonix on the evening of Friday 28 August. To place your visit within the season, our article on when to do the Tour du Mont-Blanc sets out conditions month by month, and they hold for this sector too.

Lac Blanc in winter

The lake remains reachable on snowshoes or ski touring gear, but in an entirely different setting: the surface is frozen and snow-covered, the landscape white throughout. The la Flégère cable car then serves the sector only when the ski area is open, and the col des Montets road can be shut. Above all, these slopes are avalanche ground: a winter outing to Lac Blanc is not a walk, it is prepared like a snow route, with the kit and the bulletin reading that go with it. If in any doubt, ring the Office de Haute Montagne (la Chamoniarde) before you go.

Swimming, dogs, bivouac: what the reserve says

Lac Blanc and the lacs des Chéserys lie within the Réserve naturelle nationale des Aiguilles Rouges, 3,276 hectares protected by ministerial order of 23 August 1974. It came out of a local initiative: the intercommunal reserve of the col des Montets, set up in 1971 by a few determined locals, before the State took it on three years later. In practice, three things follow.

Swimming is prohibited. Since the prefectural order of 22 May 2025, swimming and boating are banned at Lac Blanc and at the lacs des Chéserys. These high lakes are fragile places, and the sun cream and other products we carry on our skin can pollute them (studies are under way in the lakes of the Écrins). At Lac Blanc there is a more prosaic reason on top: the refuge pumps its water straight out of the lake and cooks with it. Whatever you swim in ends up on the plate of the people staying the night. Enjoy the water from the bank.

Dogs are not admitted, even on a lead. The rule applies across the reserve, wardens enforce it and the fines are not trivial. If you are travelling with a dog, arrange care for the day or pick another walk outside the reserve. The return on that strictness is plain on the ground: ibex and chamois are numerous and will let you get reasonably close, particularly early on.

A bivouac cannot go just anywhere. From 1 June to 30 September it is banned throughout the Aiguilles Rouges reserve, apart from a few sectors open by reservation. At Lac Blanc itself the answer is therefore no, and that is the main disappointment for those who carry a tent up. The nearest permitted sector is the Chéserys, thirty tents maximum, and only around the upper lake: at the lower lakes the bivouac is banned, and ropes laid on the ground mark the line not to cross. Further south, the lac Cornu and the Lacs Noirs (fifteen tents) or the col de Bellachat and the lac du Brévent (twenty-five) work the same way.

Booking is free, advised, and done at reserve-bivouac74.fr, one place per tent. After that, the tent goes up at 7pm and comes down at 9am the following morning, even if you are staying several nights. Fires and drones are banned, stoves remain permitted, and your rubbish goes back down with you: the refuge will not take it. Outside the zones or the hours, a warden's check costs €68. Camping, that is several nights in the same spot, stays prohibited everywhere in the reserve.

Zones, quotas and orders change from season to season, and the communes add their own rules on top of the reserve's: at Vallorcine, a municipal order bans the bivouac across part of the territory. Check the official site before going up with a tent. Our article on bivouac on the Tour du Mont-Blanc sets these rules within the circuit as a whole.

Staying at the Refuge du Lac Blanc

Right on the water, the Refuge du Lac Blanc (2,352 m) lets you split the walk over two days and, above all, have the lake to yourself at dawn and dusk, once the day walkers have gone down. That is the best moment to watch the Drus and the Aiguille Verte catch fire in the water. The refuge has dormitories and a kitchen, and serves drinks and meals through the day. For 2026 it gives its season as 5 June to 1 November. Allow around €70 for half board (bed, dinner and breakfast), to confirm when booking.

Capacity is limited and the place is much in demand: booking is essential, often several weeks ahead for a summer weekend. It is done online at refugelacblanc.com or on 07 81 32 36 55. To widen the choice, la Flégère and Les Praz have other accommodation lower down, from bunkhouse to B&B, and our overview of the Tour du Mont-Blanc mountain huts lists the options in the sector.

Our notes from the ground

• Start early. The first cabin is at 8.20am in high season. Taking it means arriving at the lake around 10.30, just as the bulk of the crowd is only starting up the path. Earlier still, on foot or by sleeping at the refuge, and you get the low light and the lake to yourself.
• Water, or the means to treat it. No fountain or made-up spring on the route, and while the refuge sells drinks, it will not resupply you on the way up. Entirely self-sufficient, allow 1 to 1.5 litres per person from la Flégère, and nearer 2.5 litres on the long routes in hot weather. The water is there nonetheless: the lakes hold it all season and the streams run in addition in early summer. Lac Blanc is in fact where the refuge draws its own, and the order targets swimming and boating, not the filling of a bottle. Clear water is not therefore safe water: filter or treat it before drinking.

• A windproof, always. At 2,352 m the wind gets up quickly and the temperature falls the moment a cloud crosses, August included.
• Check conditions. Early and late in the season, snow on the paths changes everything. The la Flégère webcam gives you an immediate view, and the Office de Haute Montagne (la Chamoniarde) has path conditions on 04 50 53 22 08.
• Stay in the zigzags, here more than anywhere. Cutting straight down the slope of an empty valley is a pleasure, and we are not going to pretend we have never done it. What changes here is that the hillside is shared: the three-metre shortcut you allow yourself, several hundred others allow themselves on the same day. The vegetation holding the soil lets go, a runnel forms, water gets into it, and it takes years to close. Less a question of morals than of numbers.

Lac Blanc, a Tour du Mont-Blanc variant

If the phrase "Tré-le-Champ ladders" means something to you, that is because Lac Blanc is not only a day walk: it sits alongside the line of the Tour du Mont-Blanc. The circuit's last stretch, between Tré-le-Champ and la Flégère, runs precisely along this hillside on the Grand Balcon Sud, and a good many TMB walkers allow themselves the detour to the lake before dropping towards the Brévent and Les Houches, the final stage.

It is this same balcony that we walk on our Tour du Mont-Blanc in 7 days, the comfortable version with selected accommodation and a guide who knows the ground. With one difference: there, Lac Blanc opens the trip rather than closing it. It is the first day's stage, up from la Flégère and then down to Argentière through the forest, quieter than the lake path. So from the first lunch you have opposite you the entire north side of the massif that will take six days to walk round.

Common questions about Lac Blanc

How high is Lac Blanc?

Lac Blanc lies at 2,352 metres, in the Aiguilles Rouges massif, opposite the north side of Mont-Blanc.

Is the Lac Blanc walk difficult?

It depends on the start. From la Flégère (cable car) it is a family walk of +525 m there and back, manageable from age 7. From Argentière it is markedly harder: +1,200 m and the ladder section, for walkers who are at ease with exposure.

Can you swim in Lac Blanc?

No. Swimming and boating have been banned at Lac Blanc and the lacs des Chéserys since the prefectural order of 22 May 2025, to protect these fragile high-altitude lakes.

Are dogs allowed at Lac Blanc?

No, not even on a lead. The lake is inside the Réserve naturelle des Aiguilles Rouges, where dogs are banned. Wardens check and issue fines.

How long does it take to walk up to Lac Blanc?

Allow 2 to 2 hrs 30 of ascent from la Flégère (after the cable car), 3 to 3 hrs 30 from the col des Montets, and 6 to 7 hrs for the circuit via the ladders from Argentière.

Can you get to Lac Blanc in winter?

Yes, on snowshoes or ski touring gear, but the lake is frozen, the cable car runs only with the ski area, and the slopes are avalanche ground. A winter outing is prepared and safeguarded like a snow route.

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