Eurostar From London to Paris and return in one day

I'm not the best with directions, so will let others reply. If no luck here, try over at the Trip Advisor London Forum.

I can tell you that you will be safe in London, even at 4 in the morning. Use your big-city smarts, of course, but London is very safe.

You should arrive at St Pancras for your Eurostar (not eurorail) train 45 minutes before departure.

Give yourself a little extra time if you want to pick up breakfast to eat on the train. You can take whatever food and beverages you like. The selection is better before you go through security.

Don't forget about the hour's time difference, and the currency difference, between London and Paris. (I am sure you know this but have seen posts from people who have forgotten.)

For all the information you need, see the excellent website of the Man in Seat 61, as well as the official Eurostar website.

http://www.seat61.com/London-to-Paris-by-train.htm

Hope you enjoy your holiday.

Night bus from Trafalgar Square: N91.

If on a Friday or Saturday night, night tube from Embankment (Northern Line). You could change at Euston, but might as well walk down the street to St Pancras.

Note that taking the bus is around 20 mins+ walking at each end. Walking it is around three-quarters of an hour. If you have just missed the bus (every half hour) you'd be better walking. You could cycle it in 15 minutes.

pre book a cab

Take a taxi. You can pre-book by using the Hailo app on your smartphone or online here. When we have taken the EuroStar they suggest you arrive one hour before your train departs. Leaving at 4:15 and taking a cab should be sufficiently early. Much like an airport, you go thru a security check and customs/immigration, and you have to fill out a landing card for the EU.

I'm pretty sure the Picadilly line isn't running that early. So you'll have to take a cab. Don't forget to allow a full half-hour for immigration formalities, at both ends of the train trip. (I mean, "and on the way back to London." You'll walk right off in Paris.) Check for Picadilly closing time regarding your return to London.

I want to suggest, in what I hope is a tactful way, that if you have to ask this question, you may need to do a LOT of research and preparation to make the most of a rushed day in Paris. Are you aware that your train will go to Gare du Nord, which may not be precisely where you expected to begin your sightseeing day? Will you have Euros already in your pocket? Have you studied the Paris Metro system?

Take a taxi. At that time of the morning it shouldn't take more than 15 minutes.

If you are staying in a hotel, tell them the day before and they will arrange for a taxi.

Personally, I would arrange for a 4:30AM cab as 4:00 is very early.

Thanks everyone for your help. I have been to London and Paris but have never used St. Pancras Station before.
I will take a taxi and thanks again for your comments!

I would just add that while I agree with the option of taking the cab, I would recommend you set your own reservation vs. asking the hotel to arrange it. I was staying at a highly rated, high-priced hotel in Mayfair and despite multiple assurances from staff, my reservation was never set. It was an awful feeling so early in the morning and the scramble to get a cab at that time of day was an unnecessary stress. Enjoy your trip!

My wife and I did the same trip in 2014. Pre-book a cab is a great idea and 4 a.m. should be OK given how light traffic will be. Be aware that when it comes to security and the like, the Eurostar is similar to flying to Paris -- checking bags, passports and the lot. Something to bear in mind particularly if you are tempted (which one should be) to dawdle in Paris.