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$191+ Cheap flights from Seattle (SEA) to London, ON (YXU)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/28. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
Jul 18 — Jul 251
Sat 7/18
Sat 7/25
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 June 18, 2026.

This Trip.com deal was found by Cheapflights users on 6/18. 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.
Wed 9/237:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Wed 10/76:10 am
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 6/18$381
This Trip.com deal was found by Cheapflights users on 6/18. 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.
Thu 7/27:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Wed 7/85:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 6/18$414
This Trip.com deal was found by Cheapflights users on 6/15. 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.
Wed 8/57:00 am
SEA
-
YXU
1 stop6h 45m
WestJet
Mon 8/105:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 6/15$416
This Trip.com deal was found by Cheapflights users on 6/17. 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.
Thu 8/67:00 am
SEA
-
YXU
1 stop6h 45m
WestJet
Mon 8/105:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 6/17$417
This oojo deal was found by Cheapflights users on 6/17. 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.
Thu 7/97:00 am
SEA
-
YXU
1 stop6h 45m
WestJet
Mon 7/135:55 pm
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 6/17$454
This Trip.com deal was found by Cheapflights users on 6/13. 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.
Thu 7/167:35 pm
SEA
-
YXU
1 stop6h 45m
WestJet
Tue 7/218:40 pm
YXU
-
SEA
1 stop16h 00m
WestJet
Deal found 6/13$467

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 June 18, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$381
(Trip.com)

One-way from

$191
(oojo)
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
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One-way flight from Seattle/Tacoma Intl to London
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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 June 18, 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

Wed 9/23

7:35 pm-5:20 am

1 stop6h 45m

London

Wed 10/7

6:10 am-6:45 pm

1 stop15h 35m

$381

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 8/6

7:00 am-4:45 pm

1 stop6h 45m

London

Mon 8/10

5:55 pm-9:40 am

1 stop18h 45m

$489

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 8/6

9:43 pm-4:45 pm

2 stops16h 02m

London

Mon 8/10

5:55 pm-9:40 am

1 stop18h 45m

$523

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 9/25

7:35 pm-5:20 am

1 stop6h 45m

London

Mon 9/28

5:55 pm-9:40 am

1 stop18h 45m

$545

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 9/23

7:35 pm-5:20 am

1 stop6h 45m

London

Wed 10/7

6:10 am-4:26 pm

2 stops13h 16m

$570

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 7/11

10:34 am-5:20 am

2 stops15h 46m

London

Fri 7/17

5:55 pm-9:40 am

1 stop18h 45m

$591

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/22

5:40 am-9:40 pm

2 stops13h 00m

London

Wed 9/23

3:30 pm-9:04 pm

1 stop8h 34m

$618
Quickest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 9/25

7:20 pm-9:20 am

2 stops11h 00m

London

Mon 9/28

3:30 pm-9:04 pm

1 stop8h 34m

$618

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 9/23

7:20 pm-9:20 am

2 stops11h 00m

London

Wed 10/7

3:30 pm-9:04 pm

1 stop8h 34m

$618
Cheapest one-way
Quickest one-way

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 8/28

7:00 am-4:45 pm

1 stop6h 45m

$191

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/17

Showing 1-10 of 14 resultsSorted by cheapest first
1
2
  • 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.

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 $381, WestJet can have you in London, Ontario from Seattle in 6h 45m. There are 2000 mi between Seattle and London, Ontario.

  • 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

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