SEA - LHR

C$ 328 Find Cheap Flights from Seattle 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 Seattle to London departing on 27/7. 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.
1 adult
1 adult, Economy

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 Seattle to London, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to London, as well as popular online travel agencies
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Flights Deals

Cheap Flights from Seattle to Heathrow (SEA-LHR)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle 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.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to London

Wed, 1 Oct - Tue, 14 Oct
Scandinavian Airlines Logo
4:20 p.m. - 4:00 p.m.SEA-LHR
15h 40m1 stop
Scandinavian Airlines Logo
7:30 p.m. - 2:00 p.m.LHR-SEA
26h 30m1 stop
C$ 614Scandinavian Airlines
Find Deal
Wed, 1 Oct - Tue, 14 Oct
Scandinavian Airlines Logo
4:20 p.m. - 4:00 p.m.SEA-LHR
15h 40m1 stop
Scandinavian Airlines Logo
7:50 p.m. - 2:00 p.m.LHR-SEA
26h 10m2 stops
C$ 619Scandinavian Airlines
Find Deal
Tue, 15 Jul - Tue, 22 Jul
KLM Logo
1:30 p.m. - 9:50 a.m.SEA-LHR
12h 20m1 stop
KLM Logo
6:30 a.m. - 11:35 a.m.LHR-SEA
13h 05m1 stop
C$ 831KLM
Find Deal
Tue, 15 Jul - Tue, 22 Jul
KLM Logo
1:30 p.m. - 9:50 a.m.SEA-LHR
12h 20m1 stop
KLM Logo
9:55 a.m. - 3:50 p.m.LHR-SEA
13h 55m1 stop
C$ 833KLM
Find Deal
Mon, 7 Jul - Tue, 22 Jul
Virgin Atlantic Logo
5:35 p.m. - 11:20 a.m.SEA-LHR
9h 45mdirect
Virgin Atlantic Logo
5:25 p.m. - 7:45 p.m.LHR-SEA
10h 20mdirect
C$ 839Virgin Atlantic
Find Deal
Tue, 8 Jul - Tue, 22 Jul
Virgin Atlantic Logo
7:45 a.m. - 6:45 a.m.SEA-LHR
15h 00m1 stop
Virgin Atlantic Logo
5:25 p.m. - 7:45 p.m.LHR-SEA
10h 20mdirect
C$ 846Virgin Atlantic
Find Deal
Mon, 22 Sep - Fri, 3 Oct
Icelandair Logo
7:00 p.m. - 8:20 p.m.SEA-LHR
17h 20m1 stop
Icelandair Logo
1:05 p.m. - 8:40 p.m.LHR-SEA
15h 35m1 stop
C$ 887Icelandair
Find Deal
Mon, 22 Sep - Fri, 26 Sep
Icelandair Logo
7:00 p.m. - 8:20 p.m.SEA-LHR
17h 20m1 stop
Icelandair Logo
1:05 p.m. - 5:50 p.m.LHR-SEA
12h 45m1 stop
C$ 908Icelandair
Find Deal
Wed, 9 Jul - Fri, 3 Apr
British Airways Logo
1:30 p.m. - 6:50 a.m.SEA-LHR
9h 20mdirect
British Airways Logo
9:50 a.m. - 11:35 a.m.LHR-SEA
9h 45mdirect
C$ 937British Airways
Find Deal
Wed, 30 Jul - Wed, 27 Aug
British Airways Logo
8:20 p.m. - 1:40 p.m.SEA-LHR
9h 20mdirect
British Airways Logo
9:50 a.m. - 11:35 a.m.LHR-SEA
9h 45mdirect
C$ 982British Airways
Find Deal
Expert advice

Expert advice for your flight from Seattle to London

 
Snippets provided in this section are AI-generated based on a summarisation of KAYAK-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Airlines
Delta

Delta One offers lie-flat seats with privacy doors on select aircraft for enhanced comfort.


Delta's Wi-Fi is free for SkyMiles members on most planes, enhancing connectivity.

Read more about Deltaby Stefanie Waldek
Virgin Atlantic

Virgin's Upper Class offers fully flat beds and exclusive lounge access for luxury travel.


Virgin's Economy Delight includes extra legroom and priority boarding for added comfort.

British Airways

BA's premium economy offers 18 cm extra legroom, ideal for long-haul comfort.


BA's Club World provides priority boarding and enhanced meal service for a premium experience.

Airports
SEA

Use the SEA Spot Saver for free expedited security screening. Book online or via the flySEA app for faster access.

Read more about SEAby Harriet Baskas
LHR

Take the Elizabeth Line from Heathrow to central London for a cost-effective journey. It's half the price of the Express.

Read more about LHRby Duncan Madden
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Delta

Stefanie Waldek

Stefanie Waldek

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Read more
Laura Ratliff

Laura Ratliff

Expert on Virgin Atlantic

Laura Ratliff

Laura Ratliff

Laura Ratliff is a New York-based writer and editor. She lives in downtown Brooklyn with her husband and their beloved dogs. Originally from Texas, she now considers New York City her home. She typically spends more than 200,000 miles on a plane each year and stays in plenty of hotels.

Read more
Duncan Madden

Duncan Madden

Expert on British Airways and LHR

Duncan Madden

Duncan Madden

Duncan is a freelance travel writer, copywriter and book author in constant search of travel stories and the perpetual sensation of being on holiday. He’s never happier than when on a dusty trail in search of empty waves or ducking under the piste tape in search of snowbound solitude. British born, living in Germany, but happiest heading for the horizon. His first book, Found in Translation, explores the etymologies and stories of country names around the world and is out now.

Read more
Harriet Baskas

Harriet Baskas

Expert on SEA

Harriet Baskas

Harriet Baskas

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
Useful Info

KAYAK's insights & trends for Seattle to London flights

Get data-powered insights and trends into flights from Seattle to London 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 Seattle to London Heathrow Airport?

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

If your flying dates are flexible, you should consider flying to London Heathrow Airport on a Sunday, as we generally find the cheapest rates on that day for this route. On the other hand, Friday is the most expensive day to fly from Seattle to London Heathrow Airport. For your return ticket, we recommend flying on a Tuesday and avoiding Saturdays for the best deals.

What is the cheapest month to fly from Seattle 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 Seattle 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 Seattle to London Heathrow Airport is March, where tickets cost C$ 935 (return) on average. On the other hand, the most expensive months are June and July, where the average cost of round-trip tickets is C$ 1,524 and C$ 1,392 respectively.

Can I save money by flying with a layover from Seattle to London Heathrow Airport?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at C$ 1,173 on average.

How far in advance should I book a flight from Seattle 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 Seattle 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 Seattle 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 seasonAugust
Cheapest flightC$ 328
Best time to beat the crowds (11% less expensive on average)
Most popular time to fly and prices are also 0% lower on average.
Flight from Seattle to London Heathrow Airport

When to book flights from Seattle to London

Are your dates flexible? Find out the best times to travel from Seattle to London 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.

Flights from Seattle to London: the best tips from KAYAK users' own experiences

Insights shared by verified travellers who flew the route from Seattle to London 
Verified travelerFlew with British AirwaysSEA-LHRApr 2025
Make sure you have plenty of time between flights if you are delayed.
Verified travelerFlew with British AirwaysSEA-LHRApr 2024
Bring a sack lunch -- airport food was very expensive.

FAQs for booking Seattle to London Heathrow Airport flights

  • What is the cheapest flight from Seattle to London Heathrow Airport?

    In the last 3 days, the lowest price for a flight from Seattle to London Heathrow Airport was C$ 240 for a one-way ticket and C$ 449 for a round-trip.

  • Which airlines offer Wi-Fi service onboard planes from Seattle to London Heathrow Airport?

    Air France, Delta, Virgin Atlantic, American Airlines, and Lufthansa offer inflight Wi-Fi service on the Seattle to London Heathrow Airport flight route.

  • Which aircraft models fly most regularly from Seattle to London Heathrow Airport?

    The Boeing 787-10 Dreamliner is the aircraft model that flies most regularly on the Seattle to London Heathrow Airport flight route.

  • Which airline alliances offer flights from Seattle to London Heathrow Airport?

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

  • On which days can I fly direct from Seattle to London Heathrow Airport?

    There are direct flights from Seattle to London Heathrow Airport on a daily basis.

  • Which is the best airline for flights from Seattle to London, KLM or Virgin Atlantic?

    The two airlines most popular with KAYAK users for flights from Seattle to London are KLM and Virgin Atlantic. With an average price for the route of C$ 934 and an overall rating of 7.8, KLM is the most popular choice. Virgin Atlantic is also a great choice for the route, with an average price of C$ 1,006 and an overall rating of 7.4.

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

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Seattle 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 Seattle is likely to change within 7 days, so travellers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Seattle 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 Seattle with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Seattle 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 Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Seattle to London Heathrow Airport

  • Looking for a cheap flight? 25% of our users found flights on this route for C$ 570 or less one-way and C$ 1,018 or less round-trip.

Prefer to fly direct from Seattle to London Heathrow Airport?

Find which airlines fly direct from Seattle/Tacoma Intl Airport to London Heathrow Airport, which days they fly and book direct flights.

Direct departures

Seattle/Tacoma Intl to London Heathrow

Monday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Tuesday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Wednesday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Thursday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Friday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Saturday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Sunday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

See more nonstop flights

Direct returns

London Heathrow to Seattle/Tacoma Intl

Monday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Tuesday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Wednesday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Thursday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Friday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Saturday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

Sunday

Aer Lingus,Aeromexico,Air France, +9 more

Aer Lingus,Aeromexico, +10 more

See more nonstop flights
See more nonstop flights

Top 5 airlines serving from Seattle to London

 
See real verified KAYAK customer reviews for airlines flying from Seattle 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 Seattle to London? 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.
7.8
KLMOverall score based on 1358 reviews
8.4Crew
7.8Boarding
7.7Comfort
7.2Food
7.1Entertainment
Airline reviews

Klm start boarding while somw air issue in the plan

8.0 ExcellentA, Jun 2025AMS - YYZ
Read more KLM reviews

Klm start boarding while somw air issue in the plan

Cabin crew professional, polite and friendly, boarding was seemless, but come on KLM surely you can do better than a pack of cheesy biscuits as an inflight snack

Cabin crew were excellent, very proffesional, polite and friendly, in flight snack was underwhelming, a packet of cheese biscuits, im sure KLM could run to a sandwich!

Legroom not all it could be, especially when the seat in front is reclined. Otherwise it was good, food and beverage were nice.

You should not have to pay for WiFi in business class

Transfer at Amsterdam airport is very convenient and the airport is easy to navigate. Boarding was also quick and easy. Cabin crew were excellent and the meals were good, although lacking in options.

Overall very positive. Boarding was quick and organized. Cabin was clean and seats were reasonably comfortable. Cabin crew was excellent and the meals provided were also of good quality

This fight left ahead of time which meant it arrived early which was great. Staff were very professional, but as with all these Short hop Flights the food was a disappointing snack There was no entertainment on this flight, but I did not expect any

I flew premium economy and this was a good option. Although the seats didn’t recline much, I was able to get some sleep with my head propped against the window. The food was good and the entertainment was wonderful The staff were very attentive and professional

They only had vegetarian food left on the flight which I wasn’t happy about. I didn’t get any food to eat at all.

Super friendly and helpful staff, from check-in desk to cabin crew.

Following a paid seat upgrade for enhanced comfort, I encountered an unacceptable odor in my assigned area. It took three hours for the crew to relocate me, and the replacement seat was unacceptably close to the lavatory, offering no improvement.

Good overall. Cannot fault the airlines. I have had better entertainment systems before ie ice in Emirates but it was not too bad. Food was decent and staff were friendly.

I did not fly by vergin atlantic from bangalore to vasco da gama

Your flight delayed at Heathrow n I almost missed my mother funeral.you idiots. I had to waste 10 hours in different airports. Thank your stars I'm not suing you.

Miami airport needs more thorough signage. It was a long walk from my transport point to the check in desk,

Flight took off an hour late. Had to stay on the tarmac for half an hour after landing. Both annoying.

We had an unfortunate experience where we had to leave the aircraft after boarding, shortly before the scheduled takeoff time, and re-board. The reason given was that a passenger felt ill and had to cancel their plans and therefor their luggage had to be found and removed.

We’ve used VA before many times the experience is always been good they have lovely staff and the food is always delicious.

Everything about the flight was amazing from check in to boarding entertainment was okay food we didn’t try.

Seats in premier saga class were narrow and hard. Very uncomfortable for a 5-hour flight.

The seats on this airline are sooo small, even for a petite person. I felt like the seat tilted forward and I was fighting to stay in it. The lavatory is horribly small, with a wet floor because the sink is so small you can't help but splash the water all over when washing up.

For an economy lite experience, it's by far the best I've had. New planes, clean, great destinations. Very happy to have discovered Iceland Air.

Smooth efficient airline. Think they should have their own bag drop as the queue took 30mins to bmscan and drop

Good. Lacking overhead bin space. No food offered but you can order online or in flight and pay for snacks.

No food was served for 7.5 hrs flight. When our flight changed to other airlines due to wether issue, our seats booked with no checked in luggage when I already payed for. We end up to pay 90 euro per suitcase.

The flights were in time and the bags arrived. well done

Only serving 2 small coffee in 7.5 hrs flight with very limited choice to order food.

Booked with Kayak… Economy Class it said. I had filtered for 1 checked bag. Get to boarding and it says I have Economy Light w/ no checked bags. $136 each way for baggage now. Do not use smartfares.com. Very misleading and a terrible start to this trip.

Overall good. I was surprised how easy it was to get from plain to plain in such a short time. Food choices were not so great and quite expensive. Entertainment was ok. Flights were smooth.

From boarding, to attention in flight, I couldn’t fault it.

Not having to check carry on bags when plane wasn’t full. (The told us it was)

I was in business class for the 8 hour flight where: 1. The WiFi did not work 2. The entertainment system did not work 3. We were told there were no hot drinks for the entire flight

I had an issue with the name on my ticket vs my passport name. I was very upset that the Iberia ticket clerk had no authorization to help me and I was left to fix it. It took 19 calls of persons promising to accomplish and not doing anything before I reached someone who helped me in 10 minutes. Two of them even hung up on me. I missed my original flight because of this. Terrible customer service.

The flight was delayed twice. When the crew explained about the debris causing flat tires, I was glad they took the time to change all four.

My carry-on bag was taken from me when I boarded. It was checked through to London at no charge. It took a big of shuffling, but I was glad not to need to mind it until baggage claim.

Flight boarded three hours late for no reason other than someone made a huge error in crew scheduling. We missed our connecting flight in Madrid and got zero help from American or Iberian airlines on rebooking. We had to pay for a car to take us to the Madrid train station and pay for train tickets to Santiago. We never used our booked flight to Santiago. American claims I can submit the expenses but they are not obligated to cover them. Very frustrating.

Flight delayed Service could be better Iberia staff are not really friendly

They cancelled the flight)(they said bad weather but many other flights took off) and made us wait 5 hours in line to figure out what to do. We ended up making a new flight the next day on another airlines...I hope they honor giving us our money back

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 payment system was not working so was unable to connect wifi the entire flight

everything to do with KAYAK was terrible. Your customer facing departments are utterly useless, timewasting and unhelpful.

I ordered short ribs for main course. It tasted sweet, really sweet. Horrible.

The screen didn’t work and I didn’t get the seat upgrade I paid $300 for. They were no help with that,

Paid $180 for seat selection, and selection essnt honored. Have to call for a refund.

My flights were great and the crew on them was lovely especially the London to Barcelona flight as Al & AJ were so amazingly nice. I wish they would be my crew always as they have the best customer service. Sadly both flights were delayed the first one from Vegas was because they clearly loaded the cargo wrong the plane was off balance making us 2 hours late. This made me miss my connection and sadly it was challenging rebooking while I was on the flight. I will never use Kayak again as there was no customer service number or live chat and you rebooked me on a flight 2 days later. I had my mom call BA to change it which she did after spending an hour on hold. This should not be so difficult. My second flight was an hour delayed due to not being able to disconnect the bridge from the plane but I did finally make it home.

The delay was not communicated via text and the person who helped with check in also didn’t inform me about the delay. I ended up missing my connection and it was a waste of 5 hours. The crew didn’t mention there would be someone at the gate informing of if I would be rebooked and there was no signage. Overall a very poor experience. The British Airways app was also very buggy, and didn’t work. I will avoid flying with British Airways when possible.

A little better than outward journey but mild chaos at the boarding gate because some people with boarding cards from connecting flights had cards which weren't recognised

The BA business class cabin is excellent,very comfortable for sleeping but the service could be improved.

Surly rude flight attendants. I ordered the chicken and was given a vegetarian meal with no explanation and no opportunity to change it. I tried to order another beverage and was told by the young humorless flight attendant to “wait”. And she never came back. The seats were very uncomfortable and cramped. The last time I flew British Airways was many years ago but I remember it was amazing and the crew were very charming. This was a terrible disappointment given the cost of the flight.

Everything you need to know for your flight from Seattle to London

Information on your arrival and departure airports

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