The Mont Blanc tunnel is open 24 hours a day all year long.

To allow maintenance work, the tunnel will be closed to traffic, during the following night (10:30 pm-0:00 am): from May 18th to 20th, 2015.

As follows :

Possible inconvenience from 9 pm to 10 pm and from 6 am to 7 am due to the transit of any vehicles under escort.