Day trip/tour from Paris to Normandy

I think you'll have more tour time and less in-transit time by taking trains between Paris and Bayeux rather than bussing it the whole way. Overlord Tours has a full-day itinerary designed for people who are staying in Paris. The website says that tour runs only on weekdays. You take the early train up to Bayeux (currently departing 6:56 AM from Paris-St. Lazare) and are picked up (in a van) right at the Bayeux train station. The regular tours depart from the center of Bayeux and too early for you to catch them if coming from Paris. At the end of the tour, you are dropped off at the Bayeux train station. I don't know the exact timing of that; there seem to be hourly trains, so they might target either the 5:37 PM or the 6:37 PM train. Those are both direct trains taking about 2-1/2 hours.

I don't recommend half-day tours of the invasion sites. There's considerable out-and-back driving needed to get from Bayeux to the sites, so you'd have very little time actually seeing what you want to see.

I recommend contacting Overlord as soon as you have your travel dates pinned down, because I assume the tours are scheduled based on demand. It will probably be helpful to present several possible tour dates. Do check on the cancellation policy, though.

Assuming the lunch stop is at St-Mere-Eglise, as it was on my regular tour, I recommend taking with you something that can serve as lunch so you can use your time at that stop to see the Airborne Museum. Your other options are a fairly quick, sit-down lunch at a place like a creperie (with probably no time at all for the museum) or buying a (decent) pre-made sandwich at a local bakery and consuming it on a bench (which allows some time for the museum, but you will be more rushed than if you arrive with lunch in hand). You cannot eat in the van, so if you want to see the museum, you'll be looking for a public place to eat your lunch.

Normandy is a very large place and it will take at least three hours just to drive to the area. Your planning will go more smoothly if you pick a few specific destinations and then start using Google Maps. For ideas. use the Explore Europe menu, top let of this page.
My opinion: It's too much driving for one day. Better to train to a main stop such as Caen, where you can rent a car for the next day and explore more thoroughly.
PS: The invasion sites require a full=day guided tour to be appreciated.

I should have mentioned in my original response that there are quite a lot of invasion-related museums in Normandy. I believe the two most comprehensive are the Peace Museum in Caen (a full-day affair that is fairly expensive and considered overwhelming by many, though I liked it) and the invasion museum in Bayeux (2 or more hours I'd guess). You really can't do justice to either one in conjunction with a tour of the invasion sites without spending at least 2 nights (1-1/2 days) in Bayeux. Bayeux is definitely worth the time. It also has the Bayeux tapestry, a very good cathedral and a nice, small historic center that escaped wartime destruction. The tourist office offers a walking tour.

And that's just Bayeux. There are many other interesting places in Normandy. If you think you'll be returning to France, I'd recommend skipping Normandy on this trip and giving it a generous amount of time on Trip 2.

We took a day trip from Paris and it was wonderful. Yes, you need multiple days to do Normandy justice, but if you only have one day, this is a great tour from Caen. You can book the tour with train from Paris to Caen, they will pick you up at the train station, take you to the museum in Caen where you spend a short amount of time, then head out to visit a few places in Normandy. The tour guides the day we went were all young, did a terrific job, LOVED Americans and were so respectful of what US Troops had done for France in World War II.

Will this take you everywhere in Normandy in a long day? Of course not, but not everyone has the time or desire to spend days touring sites in that beautiful region of France. You can always go back and spend days there during a later trip (which you will likely want to do after spending the day there!). Taking the train from Paris is easy, just get to the station with plenty of time to spare and get your bearings. And hope there is no rail strike!

Enjoy the experience, there is none other like it!

https://linkparis.com/normandy-d-day-tour/

See if you can find a tour that does not include the Caen Museum. With so little time to see the sites it’s a waste of time in my opinion. It covers the rise of Fascism, not the Invasion. Seeing the sites and hearing about the Invasion from your guide is a much better use of your time, in my opinion.

The museum in Caen does cover the invasion. It's just that it also covers the lead-up to the war and the period after the war (the Cold War). It's entirely possible that many people run out of time before reaching the part of the museum that covers the invasion itself. As I said, it's really a full-day experience if you want to go all-in on that museum.

I agree that if you want to see invasion sites in a single day from Paris, you should think seriously about what you are missing out on by spending time inside a large museum.

What McCraven said, except that I consider myself amongst those who think the Caen so-called "museum" is a waste of valuable time. I also think anything in Normandy is better if you can spend more than one day—most of which will simply be spent getting there and back, and a lot of the rest will just be spent driving between sights Particularly if you spend any time in and around Caen, which has very little to offer in terms of D-Day sights.

I’m with you PharmerPhil, I dislike the Caen museum, waste of precious time, the WWII museum in Bayeux is so much better, in my opinion.