Walking time as hautetraverseedebelledonne.com states it for this stage; measured on the mapped line: 4 h 15. Climb measured on the mapped line, on terrain heights. Hautetraverseedebelledonne.com
7.7 kmStage distance
856 mAscent, measured
4 h 30Official time
9Stage number
By the Habert du Mousset, the Col de la Sitre and the Col du Loup to the Lac du Crozet, then over the Col de la Pra to the hut: 6 km, 4 h 30, 950 m up, on the stage page (our line: 7.7 km). Sources disagree on the passage by the Lac du Crozet: FFRandonnée Isère says the commune lifted its rockfall ban in May 2023 and the path was restored, but Isère Attractivité's GR 738 listing, updated on 8 July 2026, still carries a map of a temporary closure between the lake and La Pra. Our line follows the usual route by the lake: check with FFRandonnée Isère or the commune of La Combe-de-Lancey before you go.
Best season: Mid-June to mid-September. The guarded huts open from about mid-June to mid-September: in 2026 La Pra from 5 June to 27 September, Jean Collet from 15 June to 19 September, the Yayla yurts from 27 June to 27 September, and Pierre du Carre and L'Oule from mid-June to mid-September; Sept-Laux stayed open until 11 October. On 13 October 2026 the guarded season is over. Sept-Laux is closed until about 1 June. Jean Collet and La Pra have no keeper and keep only a winter room: 8 places without mattresses, blankets or gas at Jean Collet (no booking; 8 euros paid at the hut), and 18 beds at La Pra, to be booked and paid online first. Pierre du Carre publishes no winter room; L'Oule stays accessible, but ask the keeper first; the Habert d'Aiguebelle publishes no dates. Out of season, plan for no meals and no keeper on the high ground, and carry food, a stove and a sleeping bag. The passes can hold snow late in the season, and La Pra advises against walking up after the first heavy snow. The summer buses into the valleys stopped on 31 August. Before you go
Facts read from the operators' own pages and OpenStreetMap on 13 October 2026. A page can change after we read it, so confirm with the hut before you rely on a date or a bed.
Stage start
Jean Collet
Staffed mountain hut · 1,950 m · three self-employed keepers
Season
2026 15 June 2026 to 19 September 2026 Open and guarded from 15 June to 19 September, the hut says; the official site adds weekends when the weather allows.Outside the season: Only the unguarded winter room: 8 places, €8 a night paid in the box behind the door, no booking. No mattresses or blankets (bed bugs in Belledonne's unguarded huts), no gas, a stove but no wood; water nearby.refugejeancollet.com, read 13 October 2026
Places
34 places in total · winter room 34 places when guarded; a winter room of 8 places.
Booking
Booking method not publishedNo bookings while it is closed for the winter. Bookings for summer 2027 open from February, the hut says.
Staffed mountain hut · 2,105 m · Fédération Française des Clubs Alpins et de Montagne (FFCAM)
Season
2026 20 February 2026 to 11 April 2026 Guarded for ski touring, 20 February to 11 April 2026.Outside the season: Only the unguarded winter room: 18 beds with blankets, no gas, no stove, water from the stream below; book and pay the night online first. Bring a stove and a warm sleeping bag.refugedelapra.ffcam.fr, read 13 October 20262026 5 June 2026 to 27 September 2026 Guarded in summer, 5 June to 27 September 2026; guarded again for ski touring from the end of February 2027, the hut says.Outside the season: Only the unguarded winter room: 18 beds with blankets, no gas, no stove, water from the stream below; book and pay the night online first. Bring a stove and a warm sleeping bag.refugedelapra.ffcam.fr, read 13 October 2026
Places
76 places in total · winter room 76 beds when guarded (the official site says up to 75); the winter room has 18 beds in one dormitory, with blankets and dry toilets, but no gas, no stove and no water inside (there is a stream below the hut).
Booking
Book onlineBook online. Outside the guarded season you must pay the night in advance online, the hut says (it also calls booking "advised" then); the official GR 738 site says booking is compulsory even when the hut is unguarded.
In the guarded season, from mid-June to mid-September, book every night: booking is compulsory at Pierre du Carre and Sept-Laux, the Habert d'Aiguebelle asks for a deposit, and La Pra must be booked even when it is unguarded. La Perrière is unguarded and cannot be booked. Out of season, as now, the huts on the ridge have no keeper and no meals: carry food, a stove, a sleeping bag and a mat, and count only on the winter rooms the huts announce (Jean Collet, 8 places; La Pra, 18 beds). Camping is tolerated on most of the range; ask the hut keepers and shepherds where. Fires are banned in the south of the range, from the Grand Colon to the Arselle; stoves are allowed.
Val d'Arc to Vizille
Espace Belledonne's eleven stages, a night at the end of each.
Loading the forecast for low point (1,673 m) and high point (2,361 m)…
Weather by month
Typical weather on this stage: at the lowest point (1,673 m) and the highest point (2,361 m). Select a month to see why it is rated as it is.
Monthly climate averages and daylight
Month
Weather
Poor
Poor
Poor
Poor
Poor
Poor
Good
Good
Good
Mixed
Poor
Poor
High point, day / night
-4°/-9°
-3°/-10°
0°/-7°
3°/-4°
8°/0°
12°/3°
15°/5°
15°/6°
10°/2°
6°/0°
0°/-5°
-2°/-8°
Low point, day / night
2°/-5°
2°/-6°
5°/-3°
7°/-1°
12°/4°
16°/7°
19°/9°
20°/10°
15°/7°
11°/4°
6°/0°
4°/-3°
Rain, mm
142
108
115
117
138
97
77
90
114
138
181
164
Snow at high point
Likely
Likely
Likely
Likely
Likely
Likely
–
–
–
Possible
Likely
Likely
Daylight
9 h 06
10 h 23
11 h 50
13 h 27
14 h 50
15 h 37
15 h 20
14 h 09
12 h 36
11 h 03
9 h 35
8 h 47
Source: TerraClimate 1991–2020 monthly averages. Averages for the area at each point’s elevation (4 km grid, corrected for height). Not a forecast or a report of current trail conditions. Snow at the high point is estimated with a simple snowpack model from these temperatures and precipitation, not observed; steep islands and high summits can hold more snow than it shows. Daylight is for the 15th of each month. Hut, transport and park seasons are separate: check them for your dates.
Before you go
Prepare for the Haute Traversée de Belledonne
Arrange your stays, food and travel first, then check conditions again near departure.
The guarded season is over
Checked on the huts' own pages on 13 October 2026: Sept-Laux stayed open until 11 October and reopens about 1 June; Jean Collet is closed for the winter, with a winter room of 8 places, €8 a night paid on site, no booking and no mattresses, blankets or gas; La Pra is unguarded, with a winter room of 18 beds that you must book and pay online first; the Yayla's season ended on 27 September; Pierre du Carre and L'Oule are guarded only from mid-June to mid-September. Jean Collet takes bookings for summer 2027 from February.
The commune of La Combe-de-Lancey closed the GR 738 by the Lac du Crozet after a rockfall in 2022. FFRandonnée Isère wrote in January 2024 that the ban was lifted in May 2023 and the path restored, with no stopping in the rockfall zone; but Isère Attractivité's GR 738 listing, updated on 8 July 2026, still carries a map of a temporary closure between the lake and La Pra. Our line follows the usual route by the lake. Check with FFRandonnée Isère or the commune before you go; the 2022 detour over the Col de Freydane was partly off-path, for experienced mountain walkers, and is not confirmed as current. Read 13 October 2026.
FFRandonnée says the GR 738 is for experienced walkers at ease in the mountains: about 10,000 m of climbing, scree and steep slopes, with few really exposed passages. The Col de la Vache (2,556 m) on stage 7 is the high point, reached by steep scree, and the passes can hold snow late in the season. Stage 2 (8 h) is the longest day, and the stage pages call stages 4 and 5 difficult.
Camping is tolerated on most of the range, but not on private land, near flocks and their guard dogs, in sensitive areas or on helicopter landing zones: ask hut keepers and shepherds. Fires are banned in the south of the range, from the Grand Colon to the Arselle, and from 15 June to 15 September within 200 m of woods; stoves are allowed. Springs can dry up late in the season: carry enough water, or tablets to treat stream water. Espace Belledonne's bivouac page, read 13 October 2026.
Espace Belledonne posts trail news (huts, bivouac, waymarks), and FFRandonnée Isère posts path notices for Isère as "Info Sentiers". On 13 October 2026 neither showed a closure on the GR 738 apart from the Lac du Crozet question above.
Google Maps journey searches, not confirmed services. A mountain endpoint may need a booked transfer or an additional walk.
To the start at Aiguebelle
Aiguebelle (Val d'Arc), in the Maurienne valley, has a TER train halt. Espace Belledonne's transport page gives sample train times between Aiguebelle and Vizille, about €18 one way, and asks you to check them with SNCF.
The N93 bus runs all year between Grenoble and Chamrousse, the end of stage 10; book it on M-Réso. Bus 86 serves Allevard all year. The summer buses to Prapoutel-Les Sept-Laux (N94), the Collet d'Allevard (N97) and Fond de France (N98) run only from 5 July to 31 August.
Buses C13, T75, 23 and T90 link Vizille with Grenoble and Gières; plan with Itinisère. Leaving a car in Vizille for more than 3 days needs a long-stay request to the municipal police.
Prepare each stage in the valley, while you still have a connection: the Habert d'Aiguebelle has no mobile network.
Keep your route and maps on your phone for places without a signal. For multi-day trips, prepare them in the installed TrailSplits app.
Open this trail in the app.Install TrailSplits, then open this trail there. On iPhone, downloads in a browser may not be available in the installed app.
Choose your route or stages. Choose Prepare offline above. Wait for the route and maps to finish downloading.
Try it before leaving coverage. Switch offline, close and reopen the app, then use My Hikes to start navigation. Repeat for every part you will need.
Saving a bookmark is not a map download. Storage can be cleared by your device; keep a backup map for remote trips.
Route & sources
Route map & sources
Espace Belledonne, the official site for walking in Belledonne, publishes the GR 738 as eleven stages from Aiguebelle (now Val d'Arc) to Vizille, with an official stage time for each, shown beside ours on every stage. Its estimated stage distances add up to 130.5 km and its climbs to about 11,075 m; its stage GPX files measure about 128 km, and FFRandonnée's article on the GR 738 gives 140 km in one place and 130 km in another. The line here is the GR 738 on OpenStreetMap (the eleven stage relations of superroute 11999802, from the planet of 11 October 2026): 131.4 km over the whole trail, cut at the eleven official stage ends. Our climb, about 9,600 m, is below the official figures because it is measured on terrain heights, which smooth out short steep steps. On stage 9 the line follows the usual route by the Lac du Crozet, where sources disagree on whether the path is open: check before you go.
Official guidance and mapped-source comparison checked 13 October 2026. Map data is a route reference, not confirmation of today's path, weather or accommodation availability.