Day trip from Paris to Mont St Michel

It can be done, but you'll have to decide for yourselves if the time spent in transit and the expense are worth it. You can leave Paris by train at 07:35, connect in Dol de Bretagne to a bus operated by SNCF (French National Rail), and arrive at Mont St-Michel at 11:10. You can depart by bus as late as 17:15, connect to a train in Rennes, and arrive in Paris at 21:20. You can easily wait until you get to Paris to buy tickets. However, if you can commit to a travel date today, you still can get discount fare tickets. Book at www.tgv-europe.com. To keep the site in English and not get bumped to the Rail Europe site which doesn't offer discount fares, choose Great Britain as your ticket collection country. You can pick up your tickets at any SNCF station or boutique in Paris.

There are bus tours, you do not get all the time you may want, but , they are easy to do,, no thinking about schedules and trains etc,, so are an option for many people. The two main well known and reputable companies are Cityrama and Parisvisions.
They offer daytrips as well as overnight ones, they are not cheap,, but you pay for the convienence of sleeping on the bus, and line skipping as tickets are all prepaid and booked etc. You can book in Paris, but the tours run every other day or so, and they do fill up, so its best to reserve at least 4-5 days ahead. Their main offices are super easy to find, on Rue Du Rivoli , just across from the Louvre-Tuilleries Gardens( just behind a statue of Joan of Arc on a horse( thats what I thought it was anyways, lol ). They also have easy to use /read websites, just google them. I have prebooked tours online and I have done it while in Paris, its all fairly simple.

There are certainly numerous easier day trip from Paris. I would agree with your husband that for 10 days, I would want to leave the city at least twice. But I would not attempt to go as far as Mont St Michel (though we did see it on a longer trip - stayed overnight - and loved it). It is simply too far away. Too much time spent in transit, and puts you on the island at the worst possible time - right in the middle of the day. Many people here comment on how underwhelming they found the experience and invariably, they were there during the tourist crush in the middle of the day. Most people who stay overnight enjoy it a great deal.

I see a lot of people asking the same or similar question but I never saw anyone suggest what I think is the best option. If you are not afraid of driving, my advice is to take the earliest train to Rennes at 6:55 from Paris. You will be in Rennes at 9:26. Then rent a car at the Rennes train station and drive to Mont Saint Michel. It's a very easy and fast journey on a free highway. You can be in MSM as early as 10:30. Then you have plenty of time to visit. If you get tired of MSM after 2 or 3 hours you have more than enough time to drive to other interesting less known places in the area like the fishing village of Cancale, the Fougeres Medieval castle, Avranches to visit the Scriptorium, Saint-Malo, or even go back to Rennes in the afternoon and enjoy some shopping in the busy historical city center.
After returning the car you can leave from Rennes as late as 9:05 PM.

The coach tours are convenient. You can generally choose one or two days. Paris Visions and CityRama are the old established tour companies from Paris

No one ever seems to mention this about MSM, but if you are going there, first consult a tide table. MSM is much more interesting at high tide than at low tide when it is surrounded by a large expanse of sand. We went late afternoon, it wasn't particularly crowded then even in late June. Two-three hours there is plenty of time. We had a rental car, there is nothing difficult about driving in that area.......For Paris day trips, you might want to order a book called An Hour from Paris which describes 20 different day trips and tells you which trains will get you there.

Anita, I am going to Paris for the first time. I regrettably don't have the time to add this on to my trip and I am almost heartbroken for it. Please go. From what I have read it is just a day trip and the sights are worth it.
Enjoy France!

Anita, I have been to Mont St. Michel - loved it - and think that Paul's suggestion sounds really COOL. Yes, during the tourist crush at mid-day, it can be hot, packed, and semi-miserable, so his idea of getting there earlier via car is brilliant! I will also note that we stayed until very late, and loved the feel of the place after most of the day trippers were gone. Had a lovely cheap dinner of crepes somewhere (I forget where - sorry!) and it was pretty magical. St. Malo was also a delight - I recommend it - so if you follow Paul's advice, you could do MSM, St. Malo, and more!