Heathrow to St Pancras

It's a very simple direct route so just right post flight!

Take the Piccadilly line (Underground) to King's Cross St. Pancras. It will take about an hour.

That Underground station is directly underneath both King's Cross and St. Pancras railway stations so just follow the signs - Eurostar signs vary from Eurostar, to International Trains, to International Departures. But there are lots of signs.

You should come out of the Underground at one end of a very long hall - just walk along there. You will pass Arrivals on your right (the trains are up above you) and then see a Marks and Spencer store on the right - turn right there and you will find departures.

Should you exit the Underground and accidentally come out in King's Cross just follow signs again - that will take you outside briefly and you will find St. Pancras on the other side of the road. The main entrance leads directly to Eurostar departures.

It is very well signposted from all directions.

Generally it's an hour from flight to exit, then an hour to St. Pancras, and Eurostar state to be there 90 minutes before departure. So you need a train time at least three and a half hours after scheduled landing and more if you want some breathing space or lunch

thank you!

If travelling on a Sunday you need to check back closer to the time in case weekend Engineering works have closed the Piccadilly line, and you have to take another route such as the Elizabeth Line instead.
Currently the TfL engineering calendar does not extend that far out. It looks like another month or so before they will announce October work.
Also in the current situation watch out 2 weeks before for any strikes on the TfL network.

The planned Piccadilly line engineering until the start of October is as follows.

Last weekend of July between Hyde Park Corner and Acton Town - so no effect, it's in the opposite direction.

Second weekend of August between Acton Town and Heathrow - so no effect, it's in the opposite direction.

Do you already have your tickets? If not, why don't you just fly from Heathrow to Paris?

We want to take the Eurostar , but you make a good point.

Just remember to have a bit of margin in case of delays or problems. If it was me I'd plan on spending some time i London as a buffer.

But even better would have been to book a flight to Paris in the first place if that is your destination.

If we fly to LHR on AA and then take a BA flight to London, do we have to go through immigration in London?

sorry I meant if we fly to LHR on AA and then to Paris on BA do we need to go through immigration?

No immigration if the two flights are on the same ticket, which they can be with AA and BA. You will go through a security check, even if the flights use the same terminal.

If you have a separate ticket for the flight to Paris, that is a “self connect” and it still should be OK, assuming you have no checked bags, and boarding passes in hand for the second flight.

https://www.heathrow.com/connecting-flights

You will change terminals but you stay airside and will be bussed between terminals. Use the connecting flight link above for directions.

Thanks, everyone, lots of moving parts here, but we are leaning towards Eurostar to Paris now. We are allowing 90 minutes to get to St Pancras and 90 minutes to check in there for our train to Paris. We would stay in Paris for a night or two before picking up a rental car and driving to Normandy and the Loire Valley. ( we've been to London and Paris and are not fans of big cities) How much time should we allow for immigration at LHR on a Sunday morning at 9:00 am local time? We are on the fence as to whether to do this all on Sunday or wait til Monday or Tuesday.
Yes, it would be a long travel day, but we did something similar last fall when we went to Belgium and The Netherlands. We flew into AMS and went to Ghent for the first few days. I know these are different animals.

Where in Normandie? Another options is to take the train from Heathrow to Portsmouth and then the ferry to Cherbourg. That will get you to Normandie without having to go through London and Paris.

If you are going to take the Eurostar on the day you land, you need to take into account flight delays / cancellations. As for immigration at LHR at least an hour, remember there is a plethora of overseas flights from the USA to LHR arriving in that time period.

Thanks All. We did look into ferries, but dates times won't work. I think we are going to stay in London a day or two before taking the Eurostar to France

I think that staying in London for at least one night is a prudent approach, acting as a buffer day if there are any major flight issues. Probably what most people would advise.

Thanks jgdh,

Can you please clarify your post for me? Are you saying we can't count on using the tube?

As with all transport systems there is always a chance things can happen - but without knowing dates it's hard to say for sure. The Piccadilly line is 99% reliable though. And at any time there can be changes - sometimes planned, sometimes unexpected. Sunday's will always the most likely day for engineering but you are looking at two or three Sundays a year for a part section.

I use the Piccadilly line regularly and despite its slightly ageing infrastructure it's decent in terms of service.

And the good news is that the Elizabeth line is a decent enough alternative - a little more expensive is all.

Thank you for your kind help. It's much clearer now.

Transport for London (TFL) posts any closures due to planned works here:
https://tfl.gov.uk/status-updates/planned-track-closures

You can check to make sure there are no closures planned on the Piccadilly line for your day of arrival in advance.

It's much more relaxed to take the Eurostar to Paris, IMO. The Tube to St Pancras is easy and the train deposits you in Paris. Also, CDG is a PITA. But most important, short interEuropean flights should be avoided whenever possible for environmental reasons.

This is perfectly doable and as that first day is kind of wasted from an overnight flight, why not? You don't say where you are flying in from, but you can check how often your flight is on time. Worst comes to worst, you have to buy a different Eurostar ticket.

Worst comes to worst, you have to buy a different Eurostar ticket.

The problem is a walk up ticket can be substantially more expensive (hundreds of dollars more) than the least expensive advance ticket. Make sure you give yourself some buffer to reduce the risk of having to pay a lot more if your flight is delayed.

I see a couple of suggestions of flying - it ends up being about the same duration once you factor in the travelling to and from the airports at either end compared with the city centre proximity of the stations and the need to be there 90 minutes before departure. I'd go flights as one ticket i.e. a bounce out but I'd go train for separate tickets. But we all have our favourite ways to travel

Spending a night or two in London is the best idea in every way, in my opinion. You can spend the day you land recovering from the flight and be ready to go full-on the next day.

And you don’t have to worry about missing your Eurostar train because your incoming flight was late. In our experience that is “the usual”: of the last 4 times we have flown into London, all within the past year, either our landing or our arrival and disembarking from the plane was significantly delayed 3 times. Once it was a late departure from the US because the incoming flight was late; once it was a delayed departure from Venice because they had to wait for an approved landing spot; and once it was a combination of having to wait for a gate after we landed, plus no staff to operate the jetway to connect to the plane door. So each time, by the time we set foot in the airport, it was 1.5 tom3 hours later than we expected.

Another benefit of this plan is it gives you options for getting into London besides the Piccadilly line, since you do not need to go straight to St. Pancras; you can book a hotel with easy access to the station but not necessarily right there. Some options would be:

Heathrow Express from LHR to Paddington (15-20 minutes), overnight there, and take the tube the short distance to St. Pancras the next morning (10 minutes). However, this is an expensive option unless you buy your HEx tix 5 months ahead and get the cheap £5.50 fare.

The new Elizabeth line will take you to Paddington or beyond, to a station like Tottenham Court Road in the heart of Bloomsbury, close to the British Museum. Lots to see and do in this area, and many hotels from which to choose. In the morning take a black cab the short distance to St. Pancras, or choose a hotel north of the British Museum close enough to St. Pancras that you can walk. ( That might be our choice).

Another option would be a National Express coach from LHR to Victoria Coach station. We did this once and it was fun, sitting upstairs in the front row seats for a nice bit of sightseeing through London.

There are other options as well, using the Piccadilly line but not all the way to St.. Pancras. Or just head there and stay in a hotel right close to the station if you have an early morning departure.

Dear Friends,

Thank you sincerely for all your help. We were able to change our AA flights to fly in and our of Paris. we each had to buy a few miles which cost us $400 plus $92.00 each in fees. We decided the experience of riding on the Eurostar was not worth the hassle. We don't care at all about not spending time in London or Paris as we have both been there and are more interested in the French countryside. We were able to rent a car at CDG. I know it may be monstrous but it's on a Sunday morning and my husband is up to the task. Thank you all dears for answering my questions. Next March we are signed up for a RS trip to Greece.

I'm glad that the time spent here has helped you make a decision that will work well for you.