The Portes du Soleil is a French-Swiss ski area that grew one lift at a time. The first one was a 25-seat cable car above Morzine in 1934, and the name comes from a 1,950 m pass between Morgins and Les Crosets. Avoriaz opened in January 1967, and in 1976 the first Portes du Soleil pass let skiers cross the border on one ticket. Today the area claims 600 km of pistes and 208 lifts across twelve villages, and you can start a day in France, have lunch in Switzerland and be back for dinner.
It isn't one resort but a ring of villages, and that decides how to visit. Morzine and Les Gets are traditional Savoyard villages on the lower west side. Avoriaz is a car-free concrete-and-timber resort at 1,800 m that sits in the middle of the map. Champéry, Les Crosets and Champoussin are the Swiss side, with mountain restaurants that quote prices in francs. Châtel is the French village on the far south-east edge, close to Switzerland. Five days is the right length: one day per sector, with the fifth kept for weather or for tired legs.
The plan runs Morzine and Les Gets, Avoriaz, Switzerland, Châtel and the Linga, then a day off the skis, and it assumes you sleep in Morzine or Avoriaz and start on Monday 18 January 2027. That week avoids the French holidays and the Serbian winter break, and Aquariaz in Avoriaz is open on Friday (it is closed on Saturday). The area is low, so the later you come in spring, the more links are shut. For the country around it, see France, and for a high, steep alternative nearby, 5 days in Chamonix.