Chamonix to Thun Road Trip Guide: Alpine Drive

The A40 from Chamonix to the A1 towards Thun crosses the Mont Blanc Tunnel, opened in 1965, connecting France to Italy via a 11.6 km subterranean passage. This drive is an Alpine theatre of shifting geology: from granite peaks to limestone karst.

The direct distance is 180 km, but the recommended scenic route via Martigny and the A9 adds 30 km. Plan 3.5–4 hours driving time, excluding stops. The highest point is the Col de la Forclaz (1526 m), where the road narrows.

The Mont Blanc Tunnel toll is €51 one-way (2025). The A9 and A1 autoroutes require a Swiss vignette (CHF 40 for 14 months). To find hidden stops, consult how to find the best stops and hidden gems between cities.

The route passes through three geological zones: the Mont Blanc massif (granite), the Rhône valley (alluvial), and the Bernese Alps (limestone). Key natural attractions:

• Mer de Glace near Chamonix: accessible by cogwheel train.
• Trient Gorge: a 200 m deep canyon with waterfalls, near Martigny.
• Lac Léman (Lake Geneva) views from A9 between Montreux and Lausanne.

UNESCO World Heritage Sites within a 30-minute detour: Lavaux Vineyard Terraces (between Lausanne and Montreux), and the Old City of Bern (25 min from Thun).

Climatic conditions vary: heavy rain possible in the Rhône valley, strong fohn wind near Lausanne. The best sunset viewpoint is at Chexbres (Lavaux) around 20:00 in summer.

Local commerce: stop at a roadside stand in Martigny for dried apricots from the Valais; in Thun, visit the Saturday market for Bernese crafts.

Road safety: the Mont Blanc Tunnel has a strict 70 km/h limit and safety patrols. On the A9/A1, traffic is moderate except near Lausanne. Night driving is safe on motorways but avoid the N205 after dark due to wildlife.

• Family stops: Swiss Vapeur Parc (Le Bouveret) is a miniature railway park; visit the Swiss Transport Museum in Lucerne (45 min detour).
• Pet-friendly: rest areas near Bex (A9) have dog exercise zones; Café du Soleil in Martigny allows dogs.
• Fatigue management: rest zones every 30 km on Swiss motorways; recommended nap spot at the Aire de la Plaine de l'Orbe (A9).

Hidden off-route spots: the village of Salvan (5 min from Martigny) has abandoned mining structures; the ruined Château de Chillon is 10 min off-route near Montreux.

Fuel stations are abundant: every 20 km on the A9 and A1, but sparse on the N205 between Chamonix and the tunnel. Total fuel cost for a petrol car: ~€40 (8 L/100 km at €1.70/L).

• Mont Blanc Tunnel: toll €51, prepayment recommended.
• Swiss vignette: must be purchased at border or tunnels.
• Fuel efficiency tip: maintain 100 km/h on autoroutes; mountain sections consume more.

Road quality is excellent: smooth asphalt on A9/A1, but the N205 has tight corners and gradient up to 7%. No toll gates on Swiss autoroutes except for vignette check. Night illumination is present on motorways but absent on secondary mountain roads.