STL - LHR

$389 Find Cheap Flights from St. Louis to London Heathrow Airport

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from St. Louis to Heathrow departing on 9/22. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
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KAYAK searches hundreds of travel sites at once for deals on flights to London Heathrow Airport

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to London.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to London.
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Flights Deals

Cheap Flight Deals from St. Louis to Heathrow (STL-LHR)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to Heathrow that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.

Recent round-trip flight deals from St. Louis to Heathrow

KAYAK's recommended round-trip deals from the most popular airlines that fly from St. Louis to Heathrow.
Discover the best prices for you by selecting your travel dates on KAYAK.
Iberia Logo
6:10 pm - 12:30 pmSTL-LHR
12h 20m1 stop
Iberia Logo
1:30 pm - 8:13 pmLHR-STL
12h 43m1 stop
$680Iberia
Find Deal
Wed, Aug 20 - Wed, Aug 27
Finnair Logo
2:01 pm - 12:30 pmSTL-LHR
16h 29m1 stop
Finnair Logo
6:10 pm - 6:21 pmLHR-STL
30h 11m2 stops
$685Finnair
Find Deal
Tue, Sep 23 - Tue, Sep 30
Delta Logo
3:30 pm - 11:10 amSTL-LHR
13h 40m1 stop
Delta Logo
11:30 am - 11:39 pmLHR-STL
18h 09m2 stops
$699Delta
Find Deal
Wed, Aug 20 - Wed, Aug 27
British Airways Logo
1:16 pm - 7:55 amSTL-LHR
12h 39m1 stop
British Airways Logo
12:30 pm - 8:19 pmLHR-STL
13h 49m1 stop
$715British Airways
Find Deal
Wed, Jul 30 - Wed, Aug 13
British Airways Logo
6:05 pm - 6:25 amSTL-LHR
30h 20m1 stop
British Airways Logo
9:15 am - 7:08 pmLHR-STL
15h 53m1 stop
$718British Airways
Find Deal
Sat, Oct 11 - Tue, Oct 21
Air Canada Logo
1:30 pm - 6:30 amSTL-LHR
11h 00m1 stop
Air Canada Logo
2:05 pm - 2:19 pmLHR-STL
30h 14m2 stops
$721Air Canada
Find Deal
Tue, Sep 23 - Wed, Oct 1
Air Canada Logo
1:30 pm - 9:35 amSTL-LHR
14h 05m1 stop
Air Canada Logo
8:45 am - 7:33 pmLHR-STL
16h 48m2 stops
$722Air Canada
Find Deal
Mon, Sep 22 - Tue, Sep 30
United Airlines Logo
1:10 pm - 6:55 amSTL-LHR
11h 45m1 stop
United Airlines Logo
6:30 am - 3:26 pmLHR-STL
14h 56m2 stops
$810United Airlines
Find Deal
Wed, Sep 17 - Sat, Jan 10
United Airlines Logo
8:00 am - 6:30 amSTL-LHR
16h 30m2 stops
United Airlines Logo
8:30 am - 7:00 pmLHR-STL
16h 30m2 stops
$821United Airlines
Find Deal
Wed, Jul 30 - Wed, Aug 13
American Airlines Logo
6:47 pm - 12:30 pmSTL-LHR
11h 43m1 stop
American Airlines Logo
1:30 pm - 8:58 pmLHR-STL
13h 28m1 stop
$1,049American Airlines
Find Deal
Mon, May 12 - Sat, May 24
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KAYAK's insights & trends for St. Louis to Heathrow flights

Get data-powered insights and trends into flights from St. Louis to Heathrow to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from St. Louis to London Heathrow Airport?

The average price of all round-trip flights from St. Louis to London Heathrow Airport clicked on KAYAK for each day over the last 12 months.

For St. Louis to London Heathrow Airport, Thursday is the cheapest day to fly on average and Friday is the most expensive. Flying from London Heathrow Airport back to St. Louis, the best deals are generally found on Thursday, with Saturday being the most expensive.

What is the cheapest month to fly from St. Louis to London Heathrow Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from St. Louis to London Heathrow Airport, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from St. Louis to London Heathrow Airport is October, where tickets cost $804 (return) on average. On the other hand, the most expensive months are June and December, where the average cost of round-trip tickets is $1,218 and $1,166 respectively.

How far in advance should I book a flight from St. Louis to London Heathrow Airport?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from St. Louis to London Heathrow Airport, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from St. Louis to London Heathrow Airport, you should book around 4 weeks before departure. For the absolute cheapest price, our data suggests you should book 9 weeks before departure.

Good to know

Low seasonJanuary
High seasonMay
Cheapest flight$389
Best time to beat the crowds with an average 14% drop in price.
Most popular time to fly with an average 4% increase in price.
Flight from St. Louis to London Heathrow Airport

When to book flights from St. Louis to Heathrow

Are your dates flexible? Find out the best times to travel from St. Louis to Heathrow based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking St. Louis to London Heathrow Airport flights

  • What is the cheapest flight from St. Louis to London Heathrow Airport?

    In the last 3 days, the lowest price for a flight from St. Louis to London Heathrow Airport was $389 for a one-way ticket and $680 for a round-trip.

  • Do I need a passport to fly between St. Louis and London Heathrow Airport?

    A passport is required to fly from St. Louis to London Heathrow Airport.

  • Which airports will I be using when flying from St. Louis to London Heathrow Airport?

    St. Louis and London Heathrow Airport are both served by 1 main airport. You will leave St. Louis from Lambert-St Louis and will be arriving at London Heathrow.

  • Which aircraft models fly most regularly from St. Louis to London Heathrow Airport?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from St. Louis to London Heathrow Airport?

    oneworld, SkyTeam, and Star Alliance are the airline alliances operating flights between St. Louis and London Heathrow Airport, with SkyTeam being the most commonly used for this route.

  • What is the most popular layover when flying to London Heathrow Airport from St. Louis?

    Chicago is the most popular layover city among KAYAK users traveling from St. Louis to London Heathrow Airport.

  • Which is the best airline for flights from St. Louis to London, Delta or KLM?

    The two airlines most popular with KAYAK users for flights from St. Louis to London are Delta and KLM. With an average price for the route of $945 and an overall rating of 8.0, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $896 and an overall rating of 7.8.

  • How does KAYAK find such low prices on flights from St. Louis to London Heathrow Airport?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from St. Louis to London Heathrow Airport.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from St. Louis to London Heathrow Airport?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from St. Louis is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from St. Louis to London Heathrow Airport?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London Heathrow Airport with an airline and back to St. Louis with another airline. Booking your flights between St. Louis and LHR can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis to London Heathrow Airport?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London Heathrow Airport from St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top 5 airlines serving from St. Louis to Heathrow

 
See real verified KAYAK customer reviews for airlines flying from St. Louis to London. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from St. Louis to Heathrow? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.4
United AirlinesOverall score based on 8696 reviews
7.7Boarding
8.1Crew
7.1Entertainment
6.6Food
7.3Comfort
Airline reviews

Everything is good except the dinner and breakfast. The sandwich is very delicious. Toilet is clean, I only use one of them. Flight attendants are very nice. 👍👍

10.0 ExcellentAnonymous, Apr 2025SFO - HKG
Read more United Airlines reviews

Everything is good except the dinner and breakfast. The sandwich is very delicious. Toilet is clean, I only use one of them. Flight attendants are very nice. 👍👍

A bit rush for transit. Food and entertainment are not available

Boarding was a little difficult. The gate area at O'Hare was very small and crowded due to multiple gates in the area. Could not hear the intercom, so had to rely on signage to see when my group was boarding and the signage was blocked by passengers standing in the gate. Flight was great and we arrived in Montreal on time.

Multiple delays and not straight answer from the United team

For economy, it was very good. Staff was great, they even let some of us change seats for more leg room... Put an empty seat between us which was fantastic for a 12hr flight. Onboard entertainment was excellent, I think over 200 choices of movies/tv/etc The bad was the barely/nonfunctional wifi that cost either $16.99 or 1700 miles (full flight). It was atrocious... Definitely the worst of the last 3 long haul major airlines I was on the last few months.

Stewardess spilled orange juice on my clothes/seat no help no apology just threw napkins at me to clean the mess up. Not Happy.

Smooth flight. Boarding was chaotic. Could not hear the gate agent over the intercom. People were lined up in the wrong lines. Groups one and two were told to board through line one and group 3 through line 2. All very confusing. Once in the air, the flight was smooth. There was no entertainment option on this aircraft, even though it was a larger aircraft.

The plane pushed back from the gate on time. However, it stopped on the ramp, and we waited for over 20 minutes before the aircraft pulled back to the gate. Apparently, something of importance had to be removed from the aircraft by the gate agent. I found this to be odd. The delay was not significant, but I felt that whatever was on the aircraft that had to be taken off, should’ve been done before we pushed back from the gate.

I didn’t get on plane. Passport being processed by consulate with visa application. Tried to cancel through underpricer after purchasing cacelling for any reason. No dice, they are thieves.

Electric plugs didn't work. Entertainment system wasn't working

really bad they refused to check in luggages that I had purchased, even showing them the transaction receipt from british airways app the staff in miami was MEDIOCRE

Crew was great and responsive. Entertainment quit working with about 4 hours remaining on the flight. My seat cushion was broken.

Not very good , the stewardess were unfriendly and they don't like to be bothered. Cos was a night flight and they need to sleep.

British Airways staff are very polite and willing to help.

Two flight changes before the scheduled flight. On the day of the flight, the flight was delayed, which caused the connecting flight to be missed. Then, I was directed to another airport (CUN) and traveled to Tulum. American gave a $12 voucher for lunch. The least expensive item on the menu at a Mexican restaurant was $9.99. Driving to Tulum was a bad auto crash, and traffic was delayed two-plus hours. The bottom line is that we should have been at the hotel at noon, but it ended up at 11:30 PM.

Miami lounges were overcrowded and we were unable to get in. We only had a short time. But the banks are too tight in all American hubs

This particular flight wasn't very full at the back, so there were three seats available for spreading out and getting relatively comfortable

There were several issues with this flight. I have flown quite often internationally and I was surprised by the lack of presence of attendants other than meal and drink times. The food was not best but I feel that is the norm. We also had to get off the plane once in London via stairs and bus to the terminal. Anyone who had another flight had to then get another bus to another terminal. This causes me to miss my flight and have to rebook.

Overall boarding and debarking is a joke. I dont even bring luggage anymore on trips because you can never allow them to be place then in the overhead bin or you have to pay or you check them which is even worse having to wait for your luggage on the tarmac.

The boarding process was a nightmare and though we were traveling business class, we were in Group 2 and the organization was terrible. The Business Class on this flight was crowded and did not feel clean and nice. Overall, I would not travel Business again on the American Airline flight through British Airways Not nearly special enough for the considerable cost .

All was good except for the seats, not very comfy.

2.5 hour delay sitting in the plane on the tarmac, you tell me how the experience was

I hope these comments will find their way to AC customer experience team. Me and my spouse 50 years of aged coming back from 7 days perfect vacation... While boarding in FLL flight AC1621, one of the boarding agents (tall aged african american) man literelly yeld at my wife during the picture talking process. MAM ! STEP !! BACK !!! We are not illegal immegrants beying deported, nor are we in the millitary. We are customers returning home. This was unacceptable. While boarding in YYZ flight AC1154, one of the boarding agents (tall aged caucasian) man criticied with several complesant remarks my passport condition saying that I could not travel intl with it due to stain, decoloration, and BLOOD. My passport does not have blood on it! Yes it might be in less than perfect condition, but their are ways to talk to customer that does not imply not allow a boarding agent to be angry fathery like, or a custom agent looking at a suspicious individual. Both experience were less than acceptable for might I remind you a paying CUSTOMER returning home.

Short flight so no food or entertainment. Good landing at SFO and on time. We were told no carryon luggage yet lots of people were puting bags in overhead compartments. The rules need to be made more clear. I was on the first leg of an international flight and this is the first time I could not have carryon luggage.

This flight didn't happen for me because of overbooking.

My flight was overbooked and they would not let me board. I had to book another flight and pay the full amount of that flight. I did not get any help at all from Air Canada or United Airlines.

Comfortable seats and movies entertainment available. Better experience than the flight from Toronto to Denver.

Poor air traffic controller staffing led to a 50%reduction on flights so we got to wait 4 hrs for our flight! Very disorganized at the gate Poor communication with customers

It was delayed by almost 90 minutes and that messed up our plans but it was beyond UA’s control that is what we heard

Terrible experience, flight was delayed both ways. Limited compensation for the 5+ hour delay. Will not be flying Air Canada Rouge, and don’t recommend you do either.

Awful. The flight wasn't actually operated by Iberia, but by American Airlines. I was unable to get my boarding pass and as a result missed my connecting flight.

The seats were way too crowded. Just because I do not have the luxury of a suite, does not mean that I want to fly from Austin to London scrunched between two people and the seat in front of me in my face. Ridiculous. I should have flown with Turkish Airlines...

We travelled with Level, which is a subsidiary of Iberia. They mixed up all our seats, downgraded few from premium economy fo economy. The crew were not professional, they seem to be in a rush! Also some with an attitude

Paid for “extra room” selected seat. Wasn’t a benefit. Also was in aisle and was bumped almost every time attendants walked down aisle. Should have saved the assigned seat money and let them select.

Everything OK , except the plane left more than an hour late so I couldn’t participate in an excursion I had that morning in Brcelona

Flight from Madrid to Dakar had no onboard entertainment for a business class. Not even a single screen . That was disappointing. The WiFi only worked for the first 45 mins of the flight.

very good all round. staff, food, entertainment, punctuality all very good

The cabin crew were great very helpful and accommodating. We had a fellow passenger throw up next to us. The flight crew did an amazing job cleaning up and reseating us. We did question as to if he should have been let on the flight as his condition was likely self imposed.

online check-in was horrible and didn't work either way

Horrible. Paid for seats for my family. Iberia changed planes and never notified us that the seats we paid extra for did not even exist on the plane. We were randomly placed on the plane. Thankfully, we were seated together. Upon boarding, my youngest daughter was pulled from the line and they just arbitrarily changed her seat 7 rows back from the rest of the family. I had to wait at the gate while they tried to see us back together. One of the most uncomfortable small spaces on a plane I’ve ever experienced. When I called Iberia, they first told me that no mistake was made that the plane was never changed. Yet my receipt for my paid seats were for rows that did not even exist on this type of plane we were getting on. They said that they would reimburse my money and I would get an email, but I’ve never received any information or emails regarding a refund for the seats that I had paid extra for. Then when we arrived in Madrid, one of the pieces of luggage that we had checked in was damaged to the point that the handle that was stowed in to the luggage was broken off by the crew members handling the luggage. The crew on the plane was very nice, but as far as the rest of the experience, I would be very hesitant to ever use Iberia again.

The flight from Seattle was delayed, which made me miss my connection to Florence. I was re-booked NINE HOURS LATER!!! That’s basically a vacation day lost. British Airways needs to partner with other airlines when possible to get a more realistic travel time, if delays occur. I realize there aren’t many flights to Florence from London, so I would book differently were I to return. The actual flight from Seattle was very comfortable and the crew was great, no faults there. I enjoy British Airways, this was an anomaly.

The crew could not have been more helpful, my meal was excellent, I slept peacefully until right before landing, and the BA lounge was a godsend. The only negative I encountered was the coffee both on the plane and in the lounge. Not to my taste but that’s a personal preference.

I don’t understand why a reputable airline like BA would delegate their London flights to AA. Makes no sense to me, as most domestic carriers do such a poor job these days. Terminal 3 at LHR is a total dump

Cancelled flight minutes before boarding. Rescheduled flight was two days later

The flight attendants were EXTREMELY personable and appreciated the service, lights going off after dinner (probably the norm, but I haven’t flown evening overnight flights in a while). Thank you!

Business class seats were very dated on my plane. Very little storage, charging ports were not easily accessible, tv screen kept flopping away. Vegetarian food was disappointing: hardly any protein and severely under-seasoned. Crew was lovely.

The food was ok, but not great. They delayed boarding in Portland and did not enforce group boarding. But the crew was excellent, went above and beyond.

The food was pathetic. There wasn't much leg room and recline space for such a long flight. No tea/ coffee for a 2-3 hour connecting flight without purchasing! Really!?

Service was very good. Because I use a cane, I was allowed to use Priority Boarding. Biggest problem was extremely limited leg room in Economy class seats. For airplane food, it was alright.

Experience was good. Could have been better if we didn’t have to board an hour before the flight to ghana and miss relaxing time in the lounge. That process was very stressful

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