Key facts

Distance: 17.6 km
Ascent: +987 m
Descent: −955 m
Estimated time: 6 hr 05; hiking
Difficulty: Difficult; official rating
Route: Out and back; same way back

Profile and gradient

under 10%
10 to 20%
over 20%

Surface and path types

Surface: Paved 4%
Dirt & gravel 94%
Unknown 2%
Path types: Trail 69%
Track 25%
Road 4%
Off-network 2%

Description

The hamlet of Casset lives according to the changing colours, from the green prairies in the valley to the light blue of the Arsine glacial lakes. It is hard to imagine that just 60 years ago, the Arsine lakes did not exist and the entire site was covered by ice. Over time, plant life has colonised the new environment: purple saxifrage, creeping avens, campanula cenisia, genepi. There is even life in the cold water of the lakes. From the car park at the entrance of Casset, near the Park information centre, head up the hamlet by the main street and cross the second bridge over the Guisane, on the left. A straight track follows the Petit Tabuc stream and leads progressively from the hayfields into the woods. Beyond the barrier and the Clot du Gué bridge, a steady climb leads through the larch forest up to Grand Pré glade (1683 m), then on to the Douche lake (1901 m). The heart of the Ecrins National Park starts on the other side of the ford made of wood and stones. A winding footpath over a large area of scree gives well-deserved access to a mineral valley, populated with chamois. In the distance, on the right, the shepherd's mountain hut reminds us that the area is used for grazing. The footpath continues on the right of the valley and ends at the Arsine pass (2340 m). This is where you will leave the GR 54 to go over the frontal moraine of the Arsine glacier. From this ledge created by the movement of the glaciers, two large lakes mark the end of the route (2455 m). The Arsine glacial cirque is overlooked by majestic summits: you will marvel at Les Agneaux and the Neige Cordier Peak. Return by the same route.

Difficulty

Official rating: difficult, by Parc national des Écrins.

Getting there

Start: Le Casset (Le Mônetier-les-Bains), Le Monêtier-les-Bains (05).

Sources

Track: Parc national des Écrins, Licence Ouverte 2.0, Licence Ouverte 2.0 (Etalab) (destination.ecrins-parcnational.fr/trek/903295-Les-lacs-d-Arsine-au-depart-du-Casset). Time estimated by GPX Path with the Mac app rule, breaks not included.
Surface and path types: © OpenStreetMap contributors, ODbL, extract of 28 October 2026, matched to the track every 10 m (openstreetmap.org/copyright)
Official elevation gain: 987 m, Parc national des Écrins

The Arsine Lakes