Normandy: Coming from England/taxis in Normandy?

Best way to take the ferry from Portsmouth?

Tempted to answer literally: "duh, best way to take the ferry is to take it". Best way to get to Portsmouth is by train. plenty of frequent local trains, no need to buy tickets in advance. This will need taxis both ends (Southampton docks to Southampton station, and Portsmouth station to ferry terminal). If you have time, plenty to see in Portsmouth.

There are multiple ferry routes from Portsmouth to France: Le Havre, Caen, Cherbourg and St Malo. All operated by the same company. Details and booking here: https://www.brittany-ferries.co.uk/ferry-routes/ferries-france/portsmouth-france
You need to choose an overnight sailing with cabin(s). This will not be the QM2 - it will be a lot more utilitarian, most passengers will be drivers, lorry (truck) drivers and families.

Can we get away without renting a car? How would we get from the ferry to Bayeux?

Caen is nearest to Bayeux. However I recommend hiring a car, which may be easier in Le Havre or Cherbourg. The beaches are over a large area, it is rural with little transport. Taxis for trips of 10's of Km will cost €€€. A car allows you to stop off and view what you want. Yes, a series of guided tours from Bayeux is an opinion, which can be enhanced with 1 or 2 days with a car for other locations.
You need to do some research on the D-Day locations, as they are spread out over a large area.

P.S.: Also need to factor in, where are you going after Normandy and by what mode of transport?

From Southampton they can take the train from Southampton Central to Portsmouth Harbour or if they're feeling flush they could opt for the easier but more expensive option of a pre-booked taxi service. I would thoroughly recommend a visit the the Historic Naval Dockyard which is minutes walk from Portsmouth Harbour train station and also the D-Day museum about 15 minutes walk away, this may require an overnight stay in Portsmouth or not if they intend to take an overnight ferry.

From the harbour the easiest option is a short (minutes) taxi ride to the cross channel ferry port where there are ferries to Cherbourg, Caen, Le Havre and St Malo. The fastest crossing is the three hour Normandie Express, a catamaran to Cherbourg. Other, larger ferries usually take a more leisurely overnight journey.

I have no advice for the journey to Bayeux I'm afraid.

Caen to Bayeux is 30 kilometers by taxi or a 29 minute train ride. The train station is a bit outside the central area, so you might need a taxi once you get to Bayeux, depending on your hotel. I don't know where the train station in Caen is located in relation to the port, but you can find that on-line.
Since, Overlord Tours picks you up at your hotel, you wouldn't need to rent a car to drive from Caen to Bayeux or to see the D-Day sites.
Both your hotel and Overlord Tours should be able to give you more information about getting from the port to your hotel.
FYI, when we did the Overlord Tour, the guide was nice enough to drop one couple at the train station after the tour, so they could catch a train back to Paris.

I took an Overlord Tour in 2017 and was not picked up at my hotel.

We used a car service (www.aquacars.co.uk) to get to Portsmouth, spent a pleasant day and night enjoying the many historical nautical sights, then got the ferry the next morning to Caen. There's a bus from Quistreham, the actual ferry port in France, to the railroad station in Caen. We had reserved a car with one of the agencies right across the street from the Caen railroad station, then drove to the Churchill Hotel in Bayeux. Many D day tours start from right behind the Churchill Hotel and the famous 1066 Norman Conquest tapestry is a block or two away. The hassle free car service would take you directly to your hotel in Portsmouth and then a taxi is needed to get to the ferry terminal the next morning. If no car then a train from Caen to Bayeux is easy but a taxi might be needed at Bayeux to get to the hotel. Luggage might be an issue using trains and the ferry if you/they aren't able to manage heavy suitcases that people typically take on a cruise. There are no taxis available for side trips but the Churchill runs a day trip to Mont St. Michel, if that is of interest. We're in our mid-70's and had no problem driving in Normandy although we did take a D Day tour and then returned with our car to spend more time there. One trip started from arrival at Heathrow, thence to Portsmouth via Aqua Cars and then to Caen via the ferry. It's pretty stress free with advanced planning and renting a car mostly solves the heavy luggage issue plus gives you the freedom to go when and where you want. Good luck.

emily,

It looks like the transportation options are not going to be easy. Using Southampton as the departure point (since that's where the QE2 docks), the shortest trip appears to be a bit over six hours. Have a look at this - https://www.rome2rio.com/map/Southampton/Bayeux-Normandy-France . The transport options from Portsmouth don't look much better.

Another method that might work would be to travel by train from the Port of Southampton to London Southend airport, and use a flight to Caen (Carpiquet) with FlyBe. They may not offer flights every day so you'll have to check the website for your travel dates. That method would work better if they were going to spend a few days sightseeing in London before going to Normandy. Once in Caen, it's an easy train trip to Bayeux.

Of course, if you've just won the Lottery you could also use THIS service to get from Southampton directly to Bayeux.

They will require a Taxi from the station in Bayeux to their hotel. It's too far to walk into town, especially with luggage. If they're departing Bayeux early in the morning, I'd suggest asking their hotel staff to pre-arrange a Taxi back to the station.

As I recall, Overlord Tours often picks-up near the Churchill Hotel so staying there would be a good idea. You can confirm that with the hotel. Also, pre-booking the tours is highly recommended.

I assume they will stay in Normandy for a few days? Where do they go after that portion of the trip?

If you're interested, there is also the D-Day Museum in Portsmouth.

Thanks to all who have replied. It has been super helpful.
One caveat with this - my mother doesn't fly, hence the QM2. They will be going round trip back to England, returning on the QM2 7 days later. They want to do Normand for about 3 days, mostly the D-Day stuff and maybe Mont St. Michel. Then they will go back and spend a few days touring southern England.

I did find the Normandy Express ferry that will cross from Portsmouth to Cherbourg in 3 hours - much better than the 7 hours on the standard ferry to Caen.

From everyone's posts, I'm starting to see that renting a car in Cherbourg might just be the easiest after all. I'm going to go with them on this part so I can drive. I was trying to avoid this but given that the ferry station is separate from the train station and it doesn't seem easy to take side trips in a taxi, maybe this is the best.
New questions:
Is there a car rental at the ferry station in Cherbourg?

Best way to get to the ferry station in Portsmouth from Southampton?
I stumbled on Overlord tours on another forum but am open to other suggestions?

My mom is a slow walker. Is Mont St. Michel realistic?
Thank you!

Ahh - new wrinkle. We are coming on a Sunday and it seems it is impossible to rent a car at the Cherbourg ferry on Sundays :(
Can get one at the train station but with extra charges. I wonder how much the extra charges are?

If I have to go to the train station anyway, maybe we will try and just take the train to Bayeux and rely on taxis for the short transports .. .

If Mom is a slow walker, how does she do on cobblestones, steep bumpy narrow passage cobblestones? You need to be prepared for a very steep ascent up the hill and just as steep coming down, at Mont St Michel. You could look at youtubes for an idea.

Slow won't be the problem because everybody will be going slow.

Try Overlord - I have never heard a bad word about them in many years here.

If the weather in the Channel kicks up, the fast ferries are usually the first ones to stop. The older bigger ones mostly carry on regardless.

Sunday certainly will put a kink in it.

Being picked up at your hotel for a D-Day tour will be easy and fun; I'm not sure what the extra fees would be, but just a chance it involves collecting the key from the ticket office (when it is open) and taking what has been left for you, Hobson's Choice, in exchange for a substantial charge.

Have you asked the company?

A slow walker may find any D-Day tour a bit challenging since the van will park at various stopping points and then the group will walk--sometimes over non-level grass--to a gun emplacement, etc. However, to me it doesn't make much sense for a casual tourist (as opposed to an historian) to simply drive himself around looking at a bunch of beaches. If you decide a public tour would be too challenging and don't want to pay for a private one, you might consider getting your D-Day experience from a local museum. On balance, I think the Bayeux WWII museum is the best choice for the typical visitor.

For a broader experience, those willing to be on their feet for most of a day might prefer the Peace Museum in Caen.

I found the relatively new museum in Falaise very interesting. It focuses on civilian life during the war and covers the Resistance.

Arriving on a Sunday will make things difficult for car rentals anywhere. Even on weekdays you have to be careful not to arrive during lunch break, when the offices often close for an hour or more. And I'll echo the comments re: Mont-Saint-Michel for walkers. It is a steep, crowded, narrow, cobble-stoned road to the abbey at the top. I have seen many mobility-challenged people struggle mightily (and not look like they're having fun at all). I can also recommend the Bayeux D-day museum, and cast a vote against the Caen "Peace" Memorial. I finally went to the latter on my most recent trip, and felt it was time better spent elsewhere. Another great museum if you head out to Utah beach (West of Bayeux) is the wonderful museum right on the beach. It is built into some of the German defenses, but covers a lot of the D-day activities—including some very interesting videos of local inhabitants from the time, on living under occupation. It is my favorite museum in the area, although I have the Falaise museum on my must-see list for my next visit (June 2019, my eighth time to the area).

emily,

If you're considering a car rental, note that you'll require an International Driver's Permit for driving in France. This from the Embassy of France website.....

"You may drive with a valid U.S. driver’s license if it is accompanied by a notarized translation in French. It is strongly recommended that you carry an International Driving Permit. You must be 18 years of age or older to drive in France."

I'd also recommend a GPS unit or at least a good map. Especially on a Sunday, you might be better to stick with public transit. Also, since you'll be taking a tour of the Normandy historic sights, a car wouldn't be needed and would therefore be gathering dust and incurring rental, insurance and parking costs.