London-Paris December

By far the easiest way to travel between London and Paris is the Eurostar train. Anything else is going to take a great deal more time or involve airports--still more time than the Eurostar, but no real opportunity to see a small town unless you fly from Heathrow and choose Windsor. There are day-trip options from both cities (suitable for destinations that are small enough) that wouldn't require you to shift hotels. I might choose that option, depending on how many days I had in Paris and London. [Paragraph edited for clarity.]

Keep in mind that the days will be quite short in early December, and there's a substantial risk of blustery, wet, days (perhaps more likely along the coast?) that might be particularly unpleasant if you went somewhere with few indoor attractions. [Edited]

Eurostar ticket prices start low and climb quite high as you get closer to the travel date, so that is a possible concern at this point. I see prices of about $90 for the morning of December 3 on trainline.com, which does add on some fees. December 4 still has some trains priced at $75.

If it’s a trip for this year, I would opt for the cheapest between flying and the Eurostar, taking into account the cost of getting from an airport into London. You have left it very late to book either.

Other than stopping in Lille for a day, there isn’t an obvious stop off place. It’s December, so it will be dark at 4pm and the weather is likely to be miserable, so I would just get there ASAP.

Hallettm - The Eurostar is the fastest transport to Paris from London with no stops in between. However, as you mentioned you are not in a hurry and want to stop in a charming coastal towns of either England or France. In that case, Why don't you take a ferry from England to France with a stopover in Le Havre France before taking a train to Paris from there.

Brittany Ferries is the most popular company, offering trips from Portsmouth, England, to Le Havre, France, that take about four hours.
To get to Portsmouth Harbor Station from London, a train takes about 90 minutes, costs around £35 (about $54) and gives passengers expansive views of the rolling hills of Surrey. Portsmouth — the birthplace of Charles Dickens and the former home of H.G. Wells, Arthur Conan Doyle and Rudyard Kipling — is well worth a stop before boarding the ferry.

the daytime ferry trip is a relaxing four hours with plenty of French food from the cafe, bar or self-service restaurant.

The France portion is equally scenic, arriving in Le Havre, a Unesco World Heritage site and France’s second busiest port (where it’s easy to spend well over the price of that Eurostar ticket on lunch at the two-Michelin-starred Jean Luc Tartarin).

The final train journey from Le Havre to Paris (35 euros, or about $38) takes about two and a half hours, departing from Le Havre-Graville station and arriving at St. Lazare station in the Eighth Arrondissement in the center of the city.

https://www.tripsavvy.com/guide-to-le-havre-normandy-france-4156423

I wouldn't take a boat in December - too much chance of foul weather.

I'd get the Eurostar and then go to somewhere near Paris like Fontainebleau.

Yes, December, when the skies are so gray and the sun sets so early, doesn’t strike me as the time to be taking a leisurely ferry trip between the UK and France, either.

The Eurostar doesn’t really make for convenient stop offs. And it doesn’t sound like you have that much time anyway, so I would just buy tickets and make a straight shot between the two.

A reminder that a big transit strike is starting in France on December 5th, so I wouldn’t choose that as my travel day, either.

If you do decide on Eurostar be sure to leave enough time for check in at Gare du Nord. At least an hour, and with people getting away before the strike add more time for the backlog and congestion. Security checks and both French and British border checks before you get on the train all take time.

I wouldn't want to be on a boat in a gale or rainstorm - both likely in the Channel in December.

My usual warning about the ferries is this: I have booked five ferry trips between Normandy, the Channel Islands and England, all in May/June when the weather would be expected to be more stable than in December. Two of the five were canceled, one of them for three days running. I gather that I have been very unlucky, but a ferry cancellation during a relatively short trip would be difficult to recover from.

You could take a regular train from London St. Pancras International Station to Ashford International Station. From Ashford, you can visit the town of Canterbury, and then the next day you could take the afternoon Eurostar on to Paris from the International side of the Ashford station. Leaves twice a day at 6:24 am and 2:55 pm. I have done the reverse, getting off at Ashford on the way back from Paris. You could also take a train from London to Canterbury, and then make your way from Canterbury over to the Ashford Int. station when ready to go to Paris.

I have stayed at the Ashford International Hotel & Spa twice and liked it because of large rooms and good restaurant. There is a Sainsbury's Supermarket right behind the hotel, which is handy to pick up stuff you might need. I took a cab from the train station to the hotel, and a cab to Canterbury, although you could also take the train from Ashford to Canterbury. Canterbury is fun. Lots of restaurants, shops, bookstores, historical buildings, and pubs. I have also stayed at the Lodge Hotel on the grounds of the Canterbury Cathedral, and at the Grey Friars Lodge.

Canterbury has a very picturesque (and yes, touristy in some areas) historic district. The tourist office offers walking tours; I enjoyed the one I took. There's a stained glass museum upstairs (no elevator) at the cathedral. It was great to see some historic glass right at eye level.

Well, I was never prone to seasickness until I took a ferry from Ostend Belgium to Ramsgate/Dover England one December many moons ago. Oh. My. Word. No way would I do the Channel in winter when you've got the wonderful option of the Eurostar.

Also be aware of the announced French train strike starting Dec 4. The Eurostar is not part of this but I'd still want to be to Paris by Dec 3. Here is a thread that is being updated with news as things unfold.

https://community.ricksteves.com/travel-forum/france/paris-france-december-transport-strike-fyi

And due to the French general strike, I honestly would be wary of coming here at all December 4 or soon thereafter.

Not just for the possible effect on the Eurostar, but for the mess with local transportation during those dates and for getting back to the train station or airport when you are done here.

If I didn’t already have train tickets and or/ non-refundable hotel nights booked in Paris for Dec 5 and later, I would NOT book them and NOT come. It is going to be a mess.

Thanks you everyone for the feedback. I've definitely given up the ferry idea!! However I am wary of the transport strike. I am booked flying into London on 11/29 and out of Paris on ......yes.....12/7. Was planning on the 4-7 in Paris. Its a points/miles flight so I've never tried to change one of those but might alter the trip and avoid Paris. Any thoughts about how that is going to affect he rest of France? Thanks again- this forum is always great.

It’s a nationwide strike so it will be a mess everywhere, unfortunately. I wish I had a more positive answer.

Thanks again, everyone. I decided to bite the bullet and changed my flights so I won't fly out of Paris during the strike. . All in all not a bad deal. there was a lower points trip out there so I ended up getting miles back. each ticket cost 250 to change/fees and I ended up getting 32,000 miles back and rebooked a round trip from Pittsburgh to London.

So, now I will either take the train at the beginning of my trip and see Paris 29th - 3rd or give it up all together this time and add Wales into my December holiday trip.