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Across Vallon de They to the sources of the Vièze

Hikes · Troistorrents
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Valais/Wallis Promotion Verified partner  Explorers Choice 
  • Lac Vert
    / Lac Vert
    Photo: JB Bieuville, CC BY-ND
  • / Schafstall beim Col des Portes du Soleil
    Photo: Valais/Wallis Promotion
m 2400 2200 2000 1800 1600 1400 1200 16 14 12 10 8 6 4 2 km Lac Vert Morgins, poste Morgins, poste
Loop through the pristine Vallon de They to the sources of the River Vièze: a water-themed walk from peaceful woodland to idyllic alpine lakes.
Distance 16.8 km
5:23 h
785 m
784 m

This walk from Morgins up to the sources of the River Vièze explores the many ways in which water has shaped the landscape. Along the way, it passes mineral-rich springs, a waterfall, alpine lakes – and some charming restaurants and refuges at which to admire the scenery.

Starting in the centre of the resort, the trail leads upstream along the banks of the Vièze. Soon it passes a curiosity: the “red spring”, whose iron-rich waters brought the first tourists to Morgins back in 1820 to “take the waters”.

The trail continues upriver, passing the welcoming Cantine de They restaurant, until it reaches the upper sections of the valley. Here it zig-zags steeply uphill to the right to the top of a waterfall, the Fontaine Blanche – whose waters appear to emerge from the bare rock.

This is one of several features characteristic of a karst landscape: streams that disappear underground into sinkholes only to re-emerge downhill in the form of a spring, sinkholes and bizarre shapes sculptured in the rock by water.

Beyond, the trail climbs higher to the Lac de Chésery (whose waters feed the Fontaine Blanche via underground streams), and higher again to the Lac Vert. Here, the Refuge de Chésery (1,985 m) is a stable built in the mid-19th century and converted into a refuge in 1987. Attractions include delicious mountain cuisine and the chance to fish in the lake for brown and rainbow trout.

The trail then leads by two passes – including the Portes du Soleil, which gave its name to the whole holiday region – before descending again to La Tovassière, an alpine dairy farm and restaurant where specialities include dishes made from the local cheese.

After dropping back to the floor of the valley, the trail follows the Vièze once again into Morgins.


  • Vallon de They – idyllic, unspoilt mountain valley
  • Variety of landscapes: woodland, open pastures, alpine lakes, waterfalls and high passes
  • Multiple refreshment stops en route

NB The Refuge de Chésery is open until the end of September.

Author’s recommendation

Look out for wildlife around the Lac Vert: residents include frogs, toads, tadpoles, minnows, trout and alpine newts.
Highest point
Portes de l'hiver, 2,097 m
Lowest point
Morgins, 1,313 m
Best time of year

Safety information

Use of the trails and the information on this website is at hikers’ own risk. Local conditions may entail changes to routes. Valais/Wallis Promotion accepts no liability for the accuracy and completeness of information on this website.

For all hikes:

  • Bring a map. Download full description of this route including large-scale map by clicking on “Print” icon, top right of this page.
  • Use marked trails only, and observe all signposting – for your own safety, to safeguard grazing animals and to avoid disturbing wildlife.
  • Close gates after passing through.
  • Please be considerate to other trail users, and to the plants and animals.
  • Do not leave any waste in nature.

For mountain hikes:

  • Take extra care protecting yourself from the sun at altitude. UV radiation can be exceptionally strong, even in cloudy weather.
  • Plan hike carefully: take into consideration fitness level of each participant, weather forecast and season.
  • Weather conditions can change quickly in the mountains, without warning. Appropriate clothing is therefore essential, along with adequate supplies of food and water. In uncertain weather, turn back in good time.

For high-altitude hikes: 

  • Inform others of the route you plan to take. Whenever possible, avoid going alone.
  • Do not venture onto glaciers without a mountain guide.
  • Take note of the warning signs that point out the constant danger in river beds and along watercourses below dams and reservoirs: water levels may rise rapidly without warning.

Tips and hints

More information about the destination: 


Morgins (tourist office) (1,312 m)
2'555'104E 1'120'797N
46.237112, 6.856621
46°14'13.6"N 6°51'23.8"E
32T 334745 5122625


Morgins (tourist office)

Turn-by-turn directions

From the tourist office, initially follow the road up the valley before branching left onto a footpath after about 500 m. The trail leads along the valley floor all the way to Sassey, where it begins to climb steeply to the western sources of the Vièze – including the waterfall and two lakes – and continuing beyond to the highest point of the walk: the pass of the Portes de l’Hiver.

The trail then descends to a second pass – the Portes du Soleil – before turning north again, following another tributary of the Vièze via La Tovassière down to the floor of the valley, where it retraces the first section of the walk.


all notes on protected areas

Public transport

Train to Monthey, change onto local train to Troistorrents, then bus to Morgins. Find full timetable information at

Getting there

A9 motorway, exit 18 (St-Triphon) if driving from north or exit 19 (Bex) if approaching from south. Follow signs to Monthey and then Morgins.


Morgins village, follow the local car-park routeing in Morgins.


2'555'104E 1'120'797N
46.237112, 6.856621
46°14'13.6"N 6°51'23.8"E
32T 334745 5122625
Arrival by train, car, foot or bike

Book recommendation by the author

The tourist office in Morgins has got brochures and information material about hiking in the region.

Author’s map recommendations

SwissTopo maps 1:25’000: 1304 Val d’Illiez


We recommend: 
  • good footwear
  • clothing suitable for the weather: always carry a waterproof jacket
  • hat or cap
  • sunscreen
  • bottle for water, picnic
  • camera
  • hiking poles (optional)
  • printout of this hike (click “Print” icon, top right, to download)

For certain hikes: 

  • Swimwear

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Photos from others

16.8 km
5:23 h
785 m
784 m
Circular route Scenic Refreshment stops available Geological highlights Flora and fauna Insider tip Summit route


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