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$348+ Cheap flights from Seattle (SEA) to London, ON (YXU)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 6/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
May 24 — May 311
Sun 5/24
Sun 5/31
1 adult, Economy
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Cheap flight deals from Seattle to London

Cheapest flights from Seattle to London
Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 24, 2026.

This WestJet deal was found by Cheapflights users on 4/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/57:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Mon 6/85:55 pm
YXU
-
SEA
1 stop27h 50m
WestJet
Deal found 4/21$348
This Trip.com deal was found by Cheapflights users on 4/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/177:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Sun 5/245:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 4/19$371
This oojo deal was found by Cheapflights users on 4/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/227:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Wed 10/76:10 am
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 4/19$442
This Mytrip deal was found by Cheapflights users on 4/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/177:35 pm
SEA
-
YXU
1 stop6h 45m
Multiple Airlines
Sun 5/242:40 pm
YXU
-
SEA
3 stops22h 00m
Multiple Airlines
Deal found 4/19$524
This Air Canada deal was found by Cheapflights users on 4/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/227:20 pm
SEA
-
YXU
2 stops10h 35m
Air Canada
Wed 10/73:30 pm
YXU
-
SEA
1 stop8h 34m
Air Canada
Deal found 4/19$529
This Air Canada deal was found by Cheapflights users on 4/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/57:20 pm
SEA
-
YXU
2 stops10h 33m
Air Canada
Mon 6/83:30 pm
YXU
-
SEA
1 stop8h 38m
Air Canada
Deal found 4/20$552
This WestJet deal was found by Cheapflights users on 4/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/47:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Thu 6/115:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 4/19$557

Find flight deals from Seattle to London

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to London (YXU). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated April 24, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$348
(WestJet)
Provider with most accurate pricing for Seattle/Tacoma Intl-London flight deals.
Search Deals
Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-London flights.
Search Deals
From Seattle/Tacoma Intl to London
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to London that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated April 24, 2026.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 6/5

7:35 pm-5:20 am

1 stop6h 45m

London

Mon 6/8

5:55 pm-6:45 pm

1 stop27h 50m

$348

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 5/17

7:35 pm-5:20 am

1 stop6h 45m

London

Sun 5/24

5:55 pm-9:40 am

1 stop18h 45m

$371

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 5/17

7:35 pm-5:20 am

1 stop6h 45m

London

Sun 5/24

2:40 pm-9:40 am

3 stops22h 00m

$524
Quickest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 6/5

7:20 pm-8:53 am

2 stops10h 33m

London

Mon 6/8

3:30 pm-9:08 pm

1 stop8h 38m

$552

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 5/26

8:00 am-9:38 pm

1 stop10h 38m

London

Thu 5/28

9:30 am-9:08 pm

1 stop14h 38m

$597

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 5/26

7:00 am-9:38 pm

2 stops11h 38m

London

Thu 5/28

9:30 am-7:05 pm

2 stops12h 35m

$680

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/21

Sorted by cheapest first

Compare providers for flights from Seattle to London

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to London in April.
ProviderPrice AccuracyTrust Score*
FlightHubPrice Accuracy3 starsTrust Score*3 stars
oojoPrice Accuracy3 starsTrust Score*3 stars
Trip.comPrice Accuracy1 starTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Seattle-London, Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-London, Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-London, Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Seattle-London, Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London, Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Seattle to London

Have a flexible travel schedule? Discover the best time to fly to London from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated April 24, 2026.
Get a feel of what it's like to fly with Air Canada from Seattle to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Air Canada
7.1
Good
10,961 reviews

Boarding

7.3

Comfort

7.1

Entertainment

6.8

Overall

7.1

Crew

7.8

Food

6.3

Reviews

1 / 20
8.0
Excellent

John,Apr 2026

YVR - YOW

Crew was very attentive and meals were good. My wife required a wheel chair due to an accident on vacation. The service in Toronto was poor and Ottawa no better. Southeast Asia could teach them lots. Flight originated in Manila on ANA which was cancelled due to a mechanical issue. We were put up overnight in the Savoy Hotel with dinner and breakfast. The airline staff and hotel staff were fantastic.
Air Canada
7.1
Good
10,961 reviews
Air Canada
7.1
Good
10,961 reviews

Boarding

7.3

Comfort

7.1

Entertainment

6.8

Overall

7.1

Crew

7.8

Food

6.3

Reviews

1 / 20
8.0
Excellent

John,Apr 2026

YVR - YOW

Crew was very attentive and meals were good. My wife required a wheel chair due to an accident on vacation. The service in Toronto was poor and Ottawa no better. Southeast Asia could teach them lots. Flight originated in Manila on ANA which was cancelled due to a mechanical issue. We were put up overnight in the Savoy Hotel with dinner and breakfast. The airline staff and hotel staff were fantastic.

Related info for your journey

Find useful and relevant information for your journey from Seattle to London. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Seattle to London, Ontario?

    For as low as $348, WestJet can have you in London, Ontario from Seattle in 6h 45m. There are 2000 mi between Seattle and London, Ontario. This flight may include one or multiple stops.

  • What is the cheapest airline to fly from Seattle to London, Ontario round-trip?

    Cheapflights users have booked flights from Seattle to London, Ontario round-trip from $460.

  • Can I find deals for flights from Seattle to London that include hotel bookings?

    Yes. In addition to deals on Seattle to London flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to London?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to London.

  • Can I find deals for business class flights from Seattle to London?

    Yes. Cheapflights offers flight deals from Seattle to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

Traveling to a place near London?

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Top airline flying from Seattle to London

Discover the top airline that operate flights from Seattle to London. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated April 24, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$460Average$681FlexibilityNo cancel feeOn-time67%

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