Free access · Year-round
Lac Vert in Passy, emerald-green waters, facing Mont Blanc, Haute-Savoie

Lac Vert

Emerald-green mountain lake at 1,266 m, fringed with spruce trees and facing Mont Blanc. Listed natural site since 1909, reached from Plaine-Joux by a 3.1 km family loop.

TypeMountain lake, listed natural site
AccessFree · Open
CommunePassy
DifficultyBeginner
Duration1h (3.1 km loop, 100 m +)
ParkingFree at Plaine-Joux
DogsOn leash on the loop
StrollerMain access drivable, loop partially practicable
Best seasonJune – October

About Lac Vert

The Lac Vert is a mountain lake at 1,266 m on the commune of Passy, below the south face of the Fiz range, facing the Mont Blanc massif. Its emerald-green colour comes from cyanobacteria in the water, combined with exceptional clarity that reveals submerged trunks and vegetation.

The lake has been a listed natural site since 14 June 1909 (perimeter of about 16 ha including its shores). According to the Office National des Forêts, it formed during the Dérochoir landslide in the 15th century, which also left the five rocks emerging from its southern part. The body of water is around 110 m long and 80 m wide, with a depth of 3.5 to 9 m.

What you can do there

The Lac Vert loop

Signposted trail of about 3.1 km, 100 m +, 1 hour, beginner level. Wooden walkways on part of the tour protect the vegetation.

Photograph the Mont Blanc reflection

Wooden platform near the car park. The massif reflects in the water in calm weather. A well-known spot for photography.

Picnic by the lake

Tables and benches under cover. Several access points to the water's edge along the trail.

Trout fishing

Permitted for licence holders. Swimming is strictly forbidden to preserve the ecosystem.

Continue toward the refuges

The trail continues to the Châtelet d'Ayères refuge (20 min, 160 m + from the lake) and, further on, to Lac de Pormenaz and Lac d'Anterne in the nature reserve.

Snowshoe hiking in winter

Signposted snowshoe route from the Plaine-Joux resort, starting to the right of the Maison des Lutins. 1h30 round trip, easy.

Practical info

Address
1600 chemin des Parchets, 74190 Plaine-Joux, Passy
Coordinates
45.9500° N, 6.7518° E
Altitude
1,266 m
Opening hours
Free access year-round. In winter, on foot or snowshoes only from Plaine-Joux.
Price
Free
Parking
Plaine-Joux car park (paid during ski season). Lac Vert car park reachable by car outside winter, depending on the barrier.
Animals
Dogs allowed on leash on the loop. Sled dogs on site summer and winter. Forbidden in the lake.
Accessibility
Access by road for reduced mobility on request of the barrier code at Passy Tourist Office. Loop around the lake has walkways and uneven sections.
Swimming
Strictly forbidden
Fishing
Permitted with a licence
Shuttle
Free shuttle between the Plaine-Joux car park and Lac Vert in July and August (10am–6pm)

How to get there

By car

From exit 21 of the A40, follow signs to Plateau d'Assy then Plaine-Joux via the D43. Park at the Plaine-Joux car park. In July and August a barrier closes the road between Plaine-Joux and the Lac Vert car park; a free shuttle runs instead. Outside July–August, the road is open to cars (except in winter).

By public transport

LIHSA Y85 line Sallanches – Passy Plaine-Joux, stop "Passy Plaine-Joux", then 30 minutes on foot or shuttle in summer. Timetables at borini.com.

By bike

Mountain bike possible on the surfaced road between Plaine-Joux and Lac Vert outside winter. No dedicated cycling infrastructure.

When to visit

Lac Vert can be visited year-round, with distinct seasonal character:

  • June – September: ideal season, road and shuttle running, high attendance in July and August.
  • October: autumn colours, low attendance.
  • November – March: lake often frozen, access on foot or snowshoes from Plaine-Joux, snowy forest landscape.
  • April – May: road reopens gradually depending on snow cover.

Where to eat, drink, stay nearby

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Accommodation nearby?
Chalet, guesthouse, B&B, mountain refuge. Share your availability with visitors to Lac Vert.
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Photos of Lac Vert

Lac Vert (Hautes-Alpes).jpg
📷 K-mans · CC BY-SA 3.0 · Wikimedia Commons
Lago verde - panoramio - patano.jpg
📷 patano · CC BY-SA 3.0 · Wikimedia Commons
Lago Verde in valle Stretta - panoramio.jpg
📷 patano · CC BY-SA 3.0 · Wikimedia Commons
Inutile titolare , il lago Verde - panoramio.jpg
📷 patano · CC BY-SA 3.0 · Wikimedia Commons
Lac Vert (91028).jpg
📷 Detsed1 · CC BY-SA 4.0 · Wikimedia Commons
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Frequently asked questions

Is access to Lac Vert paid?
No. Access to Lac Vert is free and open year-round. The Plaine-Joux car park may be paid during the ski season, but the site itself is not charged.
Can I swim in Lac Vert?
No. Swimming is strictly forbidden in Lac Vert to preserve its fragile ecosystem. Sunscreen, inflatables and organic matter alter the water of a listed natural site.
Can I bring my dog to Lac Vert?
Yes. Dogs are allowed on a leash on the Lac Vert loop. They are forbidden in the water. Note: sled dogs are present on the site in summer and winter. Beyond the lake, on the way up to the refuges, the trails enter the Passy nature reserve where dogs are strictly forbidden, even on a leash.
How do I reach Lac Vert in summer?
From July to August, the road between Plaine-Joux and Lac Vert is closed to vehicles. Park at Plaine-Joux and reach Lac Vert on foot (30 min) or by free shuttle (10am–6pm). Outside July–August, the road is open to cars.
Is the Lac Vert loop family-friendly?
Yes. The Lac Vert loop is 3.1 km with 100 m of elevation, about 1 hour of walking. It is rated beginner level. Wooden walkways secure sensitive sections.
Can I fish in Lac Vert?
Yes, with a valid fishing licence. Fishing is permitted in Lac Vert, unlike swimming which is forbidden.
Why is Lac Vert green?
The emerald-green colour of Lac Vert comes from cyanobacteria (blue-green algae) in the water. The exceptional clarity of the lake accentuates the colour by revealing submerged vegetation and tree trunks.
Is Lac Vert accessible for people with reduced mobility?
Partially. People with reduced mobility can ask for the barrier code at the Passy Tourist Office, on presentation of proof, to drive to the car park right next to Lac Vert. The loop around the lake has walkways and uneven ground.
Can I visit Lac Vert in winter?
Yes. In winter, Lac Vert is reached on foot or snowshoes only from the Plaine-Joux car park. The lake is usually frozen and the landscape turns into snowy forest. Signposted route, around 1h30 round trip.
Sources

Cross-checked across multiple sources at publication date. Information may change — confirm with the official operator before a specific visit.

Published 23 avril 2026 · Last updated 23 avril 2026 · Report outdated info