One of the great assets of the Oisans is the possibility of linking together several mountain passes in a single ride, in a loop, without ever retracing one's steps. Starting from Bourg-d'Oisans, here are our finest cycling loops, ranging from accessible rides to endurance monuments, for all levels.
The La Marmotte loop (the queen)
This is the Holy Grail: Col du Glandon, Col du Télégraphe, Col du Galibier then Alpe d'Huez, which is about 174 km and 5,000 m of elevation gain. A legendary loop reserved for very well-trained cyclists, which takes place every summer during the cyclosportive The Marmotte. To be tried at least once in your life.
The Croix de Fer – Glandon loop
A great classic that's more affordable: we're climbing the Col de la Croix de Fer From Allemond, we switch to the Col du Glandon very close by (the two peaks are only 2.5 km apart), before descending back down into the Eau d'Olle valley. Guaranteed lake and alpine meadow landscapes, for an unforgettable high mountain outing.
The Sarenne loop
To ring the changes from the classic Alpe d'Huez climb: scale the 21 hairpins, then head over to the wild side Col de Sarenne before heading down towards Lac du Chambon and returning via the Romanche. A characterful loop that combines the world's most famous mountain pass with one of the most secluded, just a few hundred metres from each other.
The Two Villards Loop
Reserved for lovers of wild roads: the spectacular tunnel road of Villard-Notre-Dame and the hilltop village of Villard-Reymond, to combine for a timeless getaway above Bourg-d’Oisans. Bring lighting for the unlit tunnels.
A gentle ride: Col d’Ornon
Fancy a quiet day? The return trip to the Col d’Ornon through the Lignarre valley offers a gentle slope and a verdant setting, perfect for recovering or starting out. It can be extended towards Valbonnais for a longer loop.
Preparing your loop well
Before you set off, assess the difficulty of each mountain pass and check that the high-altitude roads are open. Our guides which mountain pass to climb according to your level and when to climb the Oisans mountain passes will help you plan a bespoke outing. Each col fact sheet provides the profile, map and GPX track to help you prepare your route.
Frequently asked questions
What is the hardest loop starting from Bourg-d’Oisans?
The La Marmotte loop (Glandon, Télégraphe, Galibier, Alpe d'Huez), with its 5,000 metres of elevation gain, is the most demanding.
Can you do an easy loop with a mountain pass?
Yes: the return trip to Col d’Ornon or the rise of Les Deux Alpes are accessible to less fit cyclists.
Do we need a GPS track for these loops?
This is recommended in the mountains. Find the GPX track for each mountain pass on the Oisans mountain passes page to build your career path.
Fancy putting together your own itinerary? Discover all the mountain passes, sorted by area, on the Oisans mountain passes page.