So sad with COVID confusion :( Should I just cancel?

This site is pretty clear on what you need to do in the UK.

https://www.gov.uk/guidance/travel-to-england-from-another-country-during-coronavirus-covid-19

Thank you for your reply. Just to clarify, does that mean that I need to show negative test result before boarding plane even though I'm vaccinated, and then once I arrive I need to take another day 2 test? So in total I have to take two tests before I can sightsee?

You must take a test before leaving the US, within 2 days of arriving in London. Before arriving in London, you must also schedule and pay for a second test to be administered AFTER you arrive in London. Day 0 is your arrival day. You must test by day 2. You cannot leave your hotel until you receive your negative PCR test, so you want to test asap. The link above has info on testing.

So if your flight is on a Monday, arriving on Tuesday (day 0)
You need to test on Sunday.
You need to test again in London by Thursday. You cannot leave your hotel until negative test results come back. No sightseeing.

With just 1 London day to sightsee, and 2 days to look at the interior walls of your hotel room, canceling the London part is certainly an understandable option. You’ve done your part to be prepared to go - got vaccinations, plus a booster. You’ll very likely test negative for Covid on all the tests. But you still need to prove it with a negative test to get on the plane, then another to let the U.K. let you stay beyond 2 days, without doing an even longer quarantine in London. Can your doctor suggest where you can get a hometown test, two days or less from your departure for Europe, or a local hospital or drugstore, or ask your local or state Health Department? You need to ensure that whatever test you take, you’ll have your results in time to be checked in to your flight.

For what it’s worth, we were originally scheduled to fly Denver to London to Bologna, Italy in September, 3 months ago. But the Italian regulations at the time said that if we arrived there on a plane from England, we’d have to quarantine for 5 days upon arrival in Italy, even though we were both double-vaxxed. We decided that was too much - stuck inside an apartment for 5 of our 7 days in Bologna. So we booked a different flight sequence on a different airline - Denver to Dallas to Rome, then rode a train from Rome to Bologna. Still had to do a test to get on the first plane, and show our CDC vaccination card to get into Italy, but no additional tests that first week. We also filled out a passenger locator form for Italy, in case they needed to track us down after we arrived. We never heard anything more about that. We did have to do a final test the night before we flew out of Rome to come home, but being vaccinated, that was merely a formality, and was passed with flying colors.

England is doing what they believe will keep them safe - and maybe that means discouraging short time visitors. Oh well, France is less stringent but also working to keep its citizens safe.

Enjoy Paris. And if you decide to go through with your original plan, enjoy your short time in London, and your Eurostar ride. Covid is affecting everybody, one way of another. Hope you can easily cancel things, if need be, and be credited or refunded if it comes to that.

Just to clarify, does that mean that I need to show negative test result before boarding plane even though I'm vaccinated

Being vaccinated means nothing, it doesn't prevent you from contracting the virus, more so with the Omicron variant so there is a requirement to prove you're not infected prior to flying. Personally I don't see the point of travelling to London for 3 days only to spend 2 of them in your hotel waiting for your test results.

I agree with JC. It’s not worth spending most of your time in London isolating in a hotel room. You would have to arrange for room service too.

The situation in the U.K. and much of Europe is deteriorating rapidly with the threat of the Omicron variant and there is increasing talk of further restrictions and lockdowns.

Usually at this time of year there would be no availability on the Eurostar, but as many are heeding the warnings about minimising travel, there do appear to be reasonably priced tickets available.

KISS- As suggested above, skip London and go to Paris for the entire trip...

Have a great trip!!!!

Thank you all for the responses! Very helpful because I am so confused :( If I decide to fly into London and then take the Eurostar train to Paris what are the steps I need to take as far as testing and quarantine? A negative test result BEFORE boarding the plane and then what do I do if I am doing directly to Paris by train? Do I quarantine in Paris? Do I test in Paris or in London before taking the train? Sorry for all the questions, I just have no idea!

And make sure you have your days/dates correct. You said you are flying to London on Tuesday, 12/15. Tuesday is the 14th, and Wednesday is the 15th.

Can you change your fight to fly straight to Paris and avoid the testing scenario in London?

Under the current policies, I believe that once you leave the London airport on foot, you’re stuck in England for 2 days, awaiting your 2-day test results. So forget the Eurostar this trip, unless you still want to hang out in your hotel room, ordering room service for meals, waiting to be allowed to catch the train for Paris.

Instead, (option One) after landing at the London airport, stay there just long enough to catch a connecting flight to Paris. Basically you’re transiting by air from the U.S. to France, with a very temporary, interim, connecting stopover at the London airport, just to change planes. You’d still need to have arranged for, and paid for, a Day 2 test to satisfy the current British regulations. That’s the price of being allowed to fly to the London airport, in order to catch your connecting flight to Paris. But you won’t actually wind up taking a test in England on Day 2, because you’ll have already flown on to France. Or, if possible, (option Two) just fly directly from the U.S. to France, bypassing the London airport and the British requirements altogether. Can you scrap your existing flight booking? Can you get a flight refund or credit? Do they have a partner airline (British Airlines‘ partner is American Airlines, for example) that can fly you from the US to Paris, without a London flight connection? Like we did in September, eliminating London altogether will eliminate a lot of the testing requirements, costs, time, and hopefully confusion. We missed out on our planned week in London, on the way to Italy, but are looking forward to another London trip in the future, hopefully with no isolation or quarantine downtime.

Oh, and don’t be sad. You’re going to Paris! :)

Just make sure you have your CDC vaccination card, and masks. And hand sanitizer. And a pack of wipes. Travel essentials at the moment ;)

The U.K. government link above directs you as to what is required including transit details.

I wonder why most of us based in Europe have been recommending this year that people only visit one country to make it easier to keep on top of Covid rule changes?!

I love London but it sounds like you should just do Paris. I would change my flight though to just go straight there.

If I remember correctly, my friend who traveled back to the UK said they were allowing you to take the day 2 test on arrival so you’d only have to quarantine until you got results which is usually less than a day. If you want to go straight to Paris, you would still have to pay for the day two test if you plan on leaving the airport. If you only have a connection in London and are staying airside, you’d only need a negative test to fly. You wouldn’t need the day two test or the passenger locator form. London has by far been the hardest country to fly into throughout covid. I’ve definitely made it a point to steer clear of the UK no matter how many tempting cheap flights popped up

As others mentioned, the uk.gov site provides information on what you need to do.
If you choose to not stay in England and proceed on to France, it would be considered landside-transit.
See below link for the section that provides information on what you need to do.

https://www.gov.uk/guidance/coronavirus-covid-19-safer-air-travel-guidance-for-passengers#landside-transit

I'm sorry but some of the answers upthread are not current.

Current UK Government regulations for landside transit - that is land at Heathrow and go immediately to St Pancras International station and onto Eurostar in your case - are at https://www.gov.uk/guidance/coronavirus-covid-19-safer-air-travel-guidance-for-passengers#transiting-through-england

They are actually quite easy to read and understand.

They read, for transit passengers, regardless of vaccination status (all below is quoted verbatim from the website above, emphasis mine):

Landside transit
Landside transit is when you pass through UK border control on arrival, but you leave the UK shortly after (usually within 24 hours). You may leave from the same airport, railway station or port where you arrived, or from a different one, so long as you travel directly to that port of departure.

You need to take a COVID-19 test before you travel to England.

You must complete a passenger locator form before you travel to England.

You need to do the following when you complete your passenger locator form.

select ‘Stay in the UK’ under the Your travel plans section
reply ‘I will be travelling for an exempt reason’ to the question about whether you are required to self-isolate on arrival
select the Exemption options, and then select ‘Transit Exemption’
This includes if you are transiting onto the Channel Islands or the Isle of Man. You may need to show evidence of onward travel and where you will be staying at the border.

When you are in England you do not need to quarantine or take any COVID-19 travel tests.

You must either:

remain within your port of entry until your departure from England
travel directly from your port of entry to another port of departure in England