(S/E) From the Granges ski lift car park, climb up to the mountain pasture following the ski lift.
When you reach a track, turn left and continue climbing towards the Bel Air woods.
(1) After four bends, leave the track and take the path on the left that leads into the Bel Air woods. Stay on this winding path, cross the woods and you will come out onto a large open space above the cable car station and a restaurant (altitude 2,050 m).
(2) Head south into the valley, pass under the Signal chairlift, stay below the rocky outcrop on the left and arrive at the edge of an artificial reservoir.
(3) Go around the reservoir on the right and continue climbing, following a route roughly parallel to the Pyramide ski lift.
(4) Pass Col de la Platta and reach Parc de la Vanoise (wide green line on IGN map).
(5) Leave the path on the left that descends to the Refuge du Grand Plan and continue on the balcony path (unobstructed view of the Vanoise massif).
(6) Descend towards the Refuge des Lacs Merlet.
(7) Arrive at Lac Merlet inférieur, pass the lake and then start a short climb to the right towards Lac Merlet supérieur, which is ideal for a break.
(8) Descend towards the first lake and pass an intersection.
(9) Head opposite along a steep path towards the Refuge du Grand Plan.
As you approach the refuge, the path gradually widens to become a beautiful track. Pass the refuge.
(10) At a hairpin bend in the track, leave the Vanoise National Park behind you, turn left and pass close to the Grande Val chalets.
Descend the long slope into the valley, crossing the stream several times, and note the curious pile of rocks before Le Biol.
(11) Further on at Biol, leave a path on your right and continue.
(12) On a short climb, leave the path to the right towards Lac de la Rosière.
Stay on the main track to reach the chalets in the Pralin district, then the car park (S/E).

Please note that at this time of year, the Merlet Lakes refuge is closed if you want to stop for a drink (however, it is of course open to hikers who decide to spend the night there)