I feel a bit sorry for people who only visit Mont St Michel as a day trip. Part of the magic of this spectacular site is seeing the way it changes colour at different times of the day and takes on a whole new image as the tide changes.
 
I spent two night there and I would like to share some of my tips for visiting Mont Saint Michel.
 
Firstly, stay for at least one night. In the evenings, you get some amazing views of the sunset from the banks on the southern side of the bridge (eastern is probably slightly better but western side also works well). And in the morning the island is a spectacular colour at sunrise from the western banks on the southern side of the bridge.
 
The tour groups start to arrive at about 9am (or a bit later) so you can walk around the island town without the crowds to get good views of the alleyways. Many businesses won't be open until later but you can visit them with other tourists.
 
Also, try to get into the Abbey as soon as it opens so it won't be too busy. There is a lot to see inside and it took me about two/three hours to go through it all (and even though I could've spent longer). The main church is amazing but it's the Merveille that really takes away your breath! I was lucky enough to get access to the roof of the church for absolutely amazing views! There are some tours that offer this experience so I would get in contact in advance and ask about it, if you're interested.
 
The other thing I would recommend doing is the Bay Crossing at low tide. You can walk it yourself and there's no problem doing that if you're prepared and take some precautions so you won't get stuck when the tide rises. But the guides that take the walk are really knowledgable and I would suggest going with one of them just so you can learn about the ecosystem here. Remember, the bay is part of the World Heritage Site as well, not just the island!