Cycling around Lac du Bourget — France’s largest natural lake — is a beautiful and largely accessible circuit with just one real challenge: the Col du Chat, a 400-metre climb on a balcony road above the lake. The classic loop covers 50 km from Le Bourget-du-Lac, or around 70 km if you start from Chambéry, with 800 metres of total elevation gain. It is one of the finest cycling routes in Savoie — and one of the most rewarding half-day rides in the French Alps.
At a glance:
- Distance: 49 km (classic loop)
- Elevation gain: 641 m
- Estimated time: 2 to 3h30
- Difficulty: accessible for moderately fit cyclists, with one real challenge — the Col du Chat. This can be avoided via the Cat Tunnel (a car-free cycle tunnel), making the route considerably easier.
- Highlights: the panorama from the Col du Chat, the Abbaye d’Hautecombe, the harbours of Bourget-du-Lac, Conjux and Châtillon, the spa town of Aix-les-Bains.
Contents:
Where to Start the Lac du Bourget Cycling Circuit
You can join the circuit at almost any point around the lake. For those arriving from further afield, the most practical starting points are:
- Bourget-du-Lac — large free car park near the campsite and beach. The most popular start point for the classic loop.
- Les Mottets — a large car park on the east shore, allowing you to warm up your legs before tackling the Col du Chat.
- Aix-les-Bains — bike hire available here if you don’t have your own.
- Chambéry — a dedicated greenway (voie verte) connects Chambéry to the Bourget-du-Lac beach, adding around 20 km to the circuit for a total of approximately 70 km.
The Route — Step by Step
The classic direction is clockwise — this is the most popular approach among cyclists and allows you to tackle the Col du Chat with fresh legs at the start of the ride, while keeping the lake views for most of the descent.
From Bourget-du-Lac, head towards the Cat Tunnel (Tunnel du Chat), either via the main road — busier but faster — or along the lakeside road through Bourdeau, which is more scenic and quieter. At the roundabout before the tunnel, take the direction of the Col du Chat.
The road climbs in hairpin bends above an increasingly blue and magnificent lake, with Aix-les-Bains and the Mont Revard plateau visible on the opposite shore. Just before the col itself, bear right at the hamlet towards the Chapelle du Mont du Chat. From the lakeshore to the high point of the pass: 6 km of climbing at an average 6% gradient (approximately 30 minutes). The road then continues north on a profile of gentle slopes punctuated by small rises.
At Ontex, a belvedere offers a beautiful view over the Abbaye d’Hautecombe and the northern end of the lake. After the viewpoint, the road descends to Saint-Pierre-de-Curtille and then Conjux on the lakeshore. At Saint-Pierre-de-Curtille, you can turn left to extend the loop through the beautiful village of Chanaz and the banks of the Canal de Savières.
After Conjux, follow the direction of Chindrieux on a long flat road with no difficulty. You pass through part of the Chautagne poplar forest — one of the largest in Europe at 740 hectares. At the roundabout after Châtillon, turn right towards Aix-les-Bains. The road rises briefly before descending to run alongside the lake on long straight sections to Brison-Saint-Innocent. The views are excellent — but this stretch carries more traffic than the western shore.
Pass through Brison either via the main road or — more pleasantly — through the village centre. Continue towards Aix-les-Bains. After the descent from Brison, at the Oliviers roundabout, turn right, cross the railway line then bear left. Continue straight ahead to reach the lakeside (passing McDonald’s on your left and a cinema on your right). Follow the cycle lane along the shore to Les Mottets, where a dedicated cycle path on the right will take you back to Bourget-du-Lac, your starting point.
Route Map and Elevation Profile
The map below shows the classic clockwise circuit. It covers approximately 50 km with 708 metres of elevation gain. The Col du Chat is the only significant climb: 370 metres at an average 6% gradient. Outside of this ascent, the route is technically undemanding — no steep sections, no sustained climbs.
Variants and Detours
Several variants can extend, shorten or enrich the classic loop:
- The Cat Tunnel (Tunnel du Chat) — a car-free cycle tunnel that bypasses the Col du Chat entirely, allowing you to continue into the Jongieux vineyards before rejoining the circuit at Saint-Pierre-de-Curtille or Chanaz. The ideal option for families or those who prefer a flatter ride.
- Jongieux vineyards — at the top of the Col du Chat, you can cross over the other side of the mountain and descend to Jongieux via a beautiful balcony road through the Savoie vineyards. After Jongieux, a short ride brings you to Chanaz alongside the Rhône, and you rejoin the main circuit via the Canal de Savières.
- Chanaz and the Canal de Savières — from Saint-Pierre-de-Curtille, a left turn at the end of the village leads to the charming canal-side village of Chanaz (sometimes called the “little Venice of Savoie”). You rejoin the main circuit at Portout, just after Conjux.
- Col de la Chambotte — at the Chaudieu roundabout (commune of Châtillon), a detour leads to the Col de la Chambotte — a magnificent viewpoint above the lake’s northern end, renowned for its sunsets and one of the finest panoramas on the entire circuit.
- ViaRhôna variant — after the Col du Chat (or the tunnel), head west towards Yenne, then cross the Cluse de La Balme to join the ViaRhôna cycle route along the Rhône. Follow it north towards Geneva and turn off towards Chanaz to rejoin the lake.
FAQ — Cycling Around Lac du Bourget
On a road bike, allow between 2 and 3h30. Fit cyclists typically complete it in under 2 hours. Your time will depend on your climbing speed, descending confidence, the type of bike you are riding and whether there is a northerly wind — which will slow you on the way out and help you home.
Yes — e-bikes are increasingly common on the circuit. However, pay attention to your battery range: the Col du Chat climb will drain the battery significantly, and you still have many kilometres ahead. You will need a bike with a range of at least 60–90 km on flat terrain.
The classic loop is approximately 50 km. Variants via Chanaz or the ViaRhôna can extend this to around 90 km.
Between 300 m (via the tunnel) and 700 m (via the Col du Chat), the circuit is moderately challenging — accessible to cyclists in reasonable shape. The Col du Chat is the only significant climb; the rest of the route is undulating but without difficult sections.
Clockwise is strongly recommended — it gives you the best lake views throughout the descent and allows you to tackle the Col du Chat with relatively fresh legs at the start of the ride.
The Abbaye d’Hautecombe (a royal abbey visible across the lake from Ontex), the Col du Chat viewpoints, the harbours of Aix-les-Bains, Bourget-du-Lac and Châtillon, the canal village of Chanaz, and the swimming beaches at Les Mottets.
There are cycle lanes on some sections, but no fully dedicated cycle path for the entire circuit. Roads are generally quiet in the mornings — except the Col du Chat road, which is popular with tourists and therefore carries more traffic. Between Chambéry and Aix-les-Bains, a greenway (voie verte) provides a traffic-free section, used between Les Mottets and Bourget-du-Lac.
Yes — the Tunnel du Chat is a car-free cycle tunnel that bypasses the col entirely, making the circuit significantly less demanding. The vineyard road on the far side is rolling but far gentler.