Mont Blanc Tunnel Closed for Over 3 Months

From Monday, 1 September at 17:00 until Friday, 12 December at 17:00, the Mont Blanc Tunnel will be completely closed to traffic. The closure is due to work associated with the second phase of the test renovation of the tunnel vault.

The works will cover two sections with a total length of 254 metres and constitute a continuation of the first test phase carried out in autumn 2024. Due to the nature of the work, the tunnel geometry, and the necessity to dismantle all technological infrastructure in the work zones, even temporary passage will not be possible. Autumn was chosen as the period least disruptive for tourism and the local economy.

The Mont Blanc Tunnel, now 60 years old, is the first major European tunnel to undergo such an advanced renovation, involving both the vault and the sub-roadway structure. The test works in 2024 and 2025 aim to determine the best methods for the tunnel’s further renovation.

It is estimated that around 90% of trucks will be diverted towards the Fréjus Tunnel, while light vehicles will be split, depending on their travel direction, between Grand-Saint-Bernard, Fréjus, and alpine passes.

The validity of all subscriptions (for 10 or 20 trips) that are active on the day the full closure begins (1 September 2025) will be automatically extended by 4 months. The extension will occur automatically, so no application will be required.