SEA - LHR

C$ 412 Find Cheap Flights from Seattle to London Heathrow Airport – Compare and Save

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 5/9. 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, 0 bags

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Everything you should know

Cheapest round-trip
C$ 957
Typical prices: C$ 846-C$ 1,278
Scandinavian Airlines
Fri 21/8Sun 23/8
SEA - LHR • 2 stops
Cheapest direct flights
C$ 1,220
Typical prices: C$ 978-C$ 1,513
Alaska Airlines
Mon 7/12Tue 26/1
SEA - LHR • Direct
Advice from real travellers
AI-powered summary based on content written by travel experts and KAYAK users. AI can make mistakes.
Virgin Atlantic Economy Delight adds legroom; BA premium economy adds 18 cm.
Delta offers free Wi-Fi for SkyMiles members on most planes on this long-haul route.
Expert advice
Expert advice
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Expert advice
Expert advice
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Top airlines
Cheapest • from C$ 957 (round-trip)
Best reviews • 7.5 score
Airline reviews
Airline reviews
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Airline reviews
Airline reviews
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Direct flights
You can fly direct with Alaska Airlines, British Airways, and others. Average duration is 9h 25m
Direct flights
Direct flights
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Direct flights
Direct flights
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Avoid delays
Most punctual • 94% on-time
Best time • Fewest delays
Insights
Insights
Insights
Insights
Top layover airports
Cheapest • Avg C$ 798 (round-trip)
Shortest trip • 11h 30m (one-way)
Insights
Insights
Insights
Insights
When to book
in advance
Our data shows that travellers who book at least 3 weeks in advance save around 29% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 24% price drop
Most popular
Good to know
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We hope you love your trip to London!
Flight Deals
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Expert advice
Flight Deals

Cheap Flights from Seattle to London (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 London 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

Fri, 21 Aug - Sun, 23 Aug
Scandinavian Airlines Logo
3:55 p.m. - 6:30 p.m.
SEA
-
LHR
18h 35m
2 stops
Scandinavian Airlines Logo
10:20 a.m. - 9:45 p.m.
LHR
-
SEA
19h 25m
2 stops
C$ 957Scandinavian Airlines
Sat, 22 Aug - Mon, 24 Aug
Scandinavian Airlines Logo
3:55 p.m. - 7:55 p.m.
SEA
-
LHR
20h 00m
2 stops
Scandinavian Airlines Logo
6:40 a.m. - 11:19 p.m.
LHR
-
SEA
24h 39m
2 stops
C$ 964Scandinavian Airlines
Sat, 12 Dec - Fri, 22 Jan
Icelandair Logo
2:35 p.m. - 7:30 p.m.
SEA
-
LHR
20h 55m
1 stop
Icelandair Logo
12:15 p.m. - 5:00 p.m.
LHR
-
SEA
12h 45m
1 stop
C$ 968Icelandair
Thu, 1 Oct - Wed, 14 Oct
Icelandair Logo
7:00 p.m. - 8:20 p.m.
SEA
-
LHR
17h 20m
1 stop
Icelandair Logo
9:25 p.m. - 5:55 p.m.
LHR
-
SEA
28h 30m
1 stop
C$ 971Icelandair
Sun, 4 Oct - Sat, 17 Oct
Icelandair Logo
7:00 p.m. - 11:55 a.m.
SEA
-
LHR
32h 55m
1 stop
Icelandair Logo
9:25 p.m. - 5:55 p.m.
LHR
-
SEA
28h 30m
1 stop
C$ 972Icelandair
Fri, 28 Aug - Sat, 5 Sep
Icelandair Logo
11:25 p.m. - 8:20 p.m.
SEA
-
LHR
12h 55m
1 stop
Icelandair Logo
9:25 p.m. - 11:45 a.m.
LHR
-
SEA
22h 20m
1 stop
C$ 974Icelandair
Fri, 28 Aug - Thu, 3 Sep
Icelandair Logo
3:40 p.m. - 8:20 p.m.
SEA
-
LHR
20h 40m
1 stop
Icelandair Logo
9:25 p.m. - 11:45 a.m.
LHR
-
SEA
22h 20m
1 stop
C$ 979Icelandair
Fri, 28 Aug - Thu, 3 Sep
Icelandair Logo
11:25 p.m. - 8:20 p.m.
SEA
-
LHR
12h 55m
1 stop
Icelandair Logo
9:25 p.m. - 11:45 a.m.
LHR
-
SEA
22h 20m
1 stop
C$ 981Icelandair
Sun, 23 Aug - Thu, 3 Sep
Icelandair Logo
3:40 p.m. - 11:55 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
9:25 p.m. - 11:45 a.m.
LHR
-
SEA
22h 20m
1 stop
C$ 982Icelandair
Thu, 17 Sep - Wed, 7 Oct
Icelandair Logo
7:00 p.m. - 11:55 a.m.
SEA
-
LHR
32h 55m
1 stop
Icelandair Logo
9:25 p.m. - 8:40 p.m.
LHR
-
SEA
31h 15m
1 stop
C$ 984Icelandair
Booking Insights

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.

How much is a round-trip flight from Seattle to London Heathrow Airport?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Seattle to London Heathrow Airport departing in August.

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 Wednesday, as we generally find the cheapest rates on that day for this route. On the other hand, Thursday is the most expensive day to fly from Seattle to London Heathrow Airport. For your return ticket, we recommend flying on a Wednesday 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 January, where tickets cost C$ 909 (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$ 1,765 and C$ 1,437 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 2 stops layover the cheapest option at C$ 1,107 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 3 weeks before departure, which saves you about 29% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Expert advice

Expert advice for your flight from Seattle to London

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Delta

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.

Duncan Madden

Duncan Madden

Expert on British Airways and LHR

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.

Laura Ratliff

Laura Ratliff

Expert on Virgin Atlantic

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.

Harriet Baskas

Harriet Baskas

Expert on SEA

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.

Good to know

Low seasonJanuary
Cheapest flightC$ 412
Best time to beat the crowds (24% less expensive on average)
Most popular time to fly and prices are also 15% 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 
MichaelFlew with Delta
SEA
-
LHR
May 2026
We like Delta, Alaska and American. Be prepared for a bit of a trek from your arrival gate to Customs and outside services. Heathrow doesn't rank high on my list of major airports.
Verified travelerFlew with American Airlines
SEA
-
LHR
Apr 2026
Heathrow is too gigantic to have less than 2 hours of layover time.
Verified travelerFlew with British Airways
SEA
-
LHR
Apr 2025
Make sure you have plenty of time between flights if you are delayed.
Verified travelerFlew with British Airways
SEA
-
LHR
Feb 2025
Don’t take a flight if you sick, or if you have no choice prepare to stay covered with mask throughout the flight
Verified travelerFlew with British Airways
SEA
-
LHR
Apr 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 5 days, the lowest price for a flight from Seattle to London Heathrow Airport was C$ 412 for a one-way ticket and C$ 957 for a round-trip.

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

    All the following airlines offer inflight Wi-Fi service on the Seattle to London Heathrow Airport flight route: Virgin Atlantic, KLM, Air France, Delta, American Airlines, Scandinavian Airlines, and JetBlue.

  • 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?

    SkyTeam is the only airline alliance operating flights between Seattle and London Heathrow Airport.

  • 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, Virgin Atlantic or Icelandair?

    The two airlines most popular with KAYAK users for flights from Seattle to London are Virgin Atlantic and Icelandair. With an average price for the route of C$ 1,005 and an overall rating of 7.5, Virgin Atlantic is the most popular choice. Icelandair is also a great choice for the route, with an average price of C$ 767 and an overall rating of 7.0.

  • 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$ 530 or less one-way and C$ 842 or less round-trip.

Prefer to fly direct from Seattle to London Heathrow Airport?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Seattle/Tacoma Intl to London Heathrow.
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

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Tuesday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Wednesday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Thursday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Friday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Saturday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Sunday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

See more nonstop flights

Direct returns

London Heathrow to Seattle/Tacoma Intl

Monday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Tuesday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Wednesday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Thursday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Friday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Saturday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

Sunday

Alaska Airlines,British Airways,Delta, +1 more

Alaska Airlines,British Airways, +2 more

See more nonstop flights

Reviews of the top airlines flying 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.
7.5
Virgin AtlanticOverall score based on 693 reviews
6.9Food
7.3Comfort
8.1Crew
7.7Boarding
7.5Entertainment
Airline reviews

Great staff great experience, made a 2 hour delay very bearable

10.0 ExcellentAnonymous, Oct 2025
LAX - LHR
Read more Virgin Atlantic reviews

Great staff great experience, made a 2 hour delay very bearable

I was my pleasure to fly virgin on my birthday for my first solo trip ever 🫶🏼

Overall, flight was excellent but check in was very slow for Premium Economy. Economy queue was shorter but we weren't allowed to use it.

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.

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.

The crew was very good. However, the equipment was a bit dated. Some of the electronics were not working. To top it, three bags didn’t arrive with me. Two of them were delivered a day later. I’m still waiting for the third bag, I was so looking forward to this virgin Atlantic flight, but, I am disappointed.

My only complaint is that the pocket in front of me was ripped and my things, like iPad and airline magazines, kept slipping to the floor.

Flight delayed yet again. Crew apathetic and unhelpful re affect on connecting flight.

i saved my points for more than 10 years in anticipation of treating myself to an upper class fight to and from london on virgin atlantic. i was shocked to find what you consider “upper class” on the dreamliner. it was, at best, a mediocre business class accommodation. it was tight and not that comfortable, with nearly no personal storage. everything was cramped and just generally disappointing. once i lucked into a 1st class upgrade to europe on lufthansa - a magical experience that found me reluctant to sleep, lest i deprive myself the joy of their setup. i expected something similar from virgin atlantic, but i could not have been more wrong. it will be the same arrangement on my flight home, but at least i know what (not) to expect. to be clear, this is only in reaction to the physical accommodations. your people were, and always are fantastic.

Damage May baggage and I report the airport agant and they see it

Crew was very friendly. Need lay flat beds! More snacks

I had no idea that my ticket only paid for my right to get on the plane. They charged me $130 for my carry-on bag because it was 1 inch too big she claimed but it wasn’t! Then they wanted another fee for everything. I had no idea that Icelandair had changed to such a bargain basement airline. I was very disappointed.

Screen didn't work, and neither did the button to tilt the seat even though the seat was comfortable

The staff was kind and helpful. There was no food, and you needed to bring your own earphones to use the entertainment, which I didn’t know.

Seat was hard and uncomfortable and the temperature too warm and uncomfortable.

Everything was good. Only issue comes from being vegan and flying. The food options are super limited.

Overall good for an economy fare. IMO the movie selection could be improved. Great that you can now connect bluetooth headphones to the entertainment system.

7 hours 15 min flight from SEA to Iceland with no inflight entertainment and no power to charge your own devices, also no meal service, not even any snacks/cookies. You have to buy food and the options are extremely limited (i.e. ham and cheese sandwich and spicy cup noodles). I didn't think Iceland air was a budget airline, maybe I was wrong, the cost of the ticket didn't feel like it though.

Very nice flight, easy connections in Keflavík, and friendly crew.

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

Information on your arrival and departure airports