Mont-Saint-Michel Tide Calendar

The table below lists the biggest Mont-Saint-Michel tides from November 2026 to April 2027. For each one it gives the date, the high-tide times and the coefficient, and it shows whether the Mont is expected to be cut off. The single largest tide in the period falls on February 22, 2027, with a coefficient of 110 at 08:05 and 20:31.

Reading the table and what a coefficient is

A tidal coefficient is a number that describes the size of a tide. The higher the number, the further the sea comes in and the further it drops back out. The table shows only high tides with a coefficient of 90 or more. That cutoff is this site’s own filter and not an official definition of a “big” tide.

The Mont-Saint-Michel tide times come from the local tourist office, which bases them on SHOM predictions for Saint-Malo, the reference port. Add about 5 minutes for the bay. All times are local French time. The tourist office had not yet published its tables for May to December 2027 when we checked. For the full official schedule, see the tourist office’s tide page.

When the Mont becomes an island

Two official bodies measure this in different ways. Normandy Tourism says the Mont-Saint-Michel island effect happens when the coefficient goes above 110. At that point the sea surrounds the rock for a few hours and access is cut off.

The Établissement public du Mont-Saint-Michel, which manages the site, uses water height at Saint-Malo instead. It sees a risk of the Mont becoming an island from 12.80 m, depending on the weather. Full insularity, with traffic banned, comes from 13 m.

The two sources also disagree on how often this happens. The tourist office says about 20 days a year, for roughly an hour in the morning and evening, when the water covers the causeway between the footbridge and the rock. The public body puts full insularity at 0 to 12 days a year. Its 2026 booklet shows no island risk in November or December 2026. No official 2027 island calendar had been published by October 28, 2026.

Seeing the tide

Plan to arrive 1-2 hours before the Mont-Saint-Michel high tide. That gives you time to watch the tidal bore, the wave that runs up the bay ahead of the rising sea. It also gets you onto the Mont before the water surrounds it. If you do get cut off, allow 1 to 1.5 hours before you can walk back.

From the Mont, the bore is best seen about 2 hours before high tide. From other points around the bay, look for it 30 minutes to 1h30 before. The tidal range here reaches about 15 meters, the largest in continental Europe. The strongest tides arrive 36 to 48 hours after full and new moons. Wind and air pressure can shift both the timing and the height, so treat every time as a guide. For what to see once you are up on the rock, read the Mont-Saint-Michel guide and the abbey page.

Safety on the bay

Never walk into the bay on your own, even close to the Mont. Go onto the sands only with a professional bay guide. The water can rise suddenly two hours before high tide.

• Check the tide times before you set out, and leave the sands well before high water.
• Do not cross channels or flooded areas, and watch out for quicksand.
• Stay off the bay in fog or storms.
• In an emergency, call 112.