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$405+ 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 10/31. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
oct. 17 — oct. 241
vie. 10/17
vie. 10/24
1 adult, Economy
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Cheap 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 septiembre 17, 2025.

Round-trip from

$405
(Air Canada)
From Seattle/Tacoma Intl to London
Search Deals

Find 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 septiembre 17, 2025.

This Air Canada deal was found by Cheapflights users on 9/16. 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.
vie. 10/318:00 pmSEA - YXU
2 stops18h 05mAir Canada
vie. 11/75:40 pmYXU - SEA
1 stop7h 36mAir Canada
Deal found 9/16$405
This Air Canada deal was found by Cheapflights users on 9/16. 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.
lun. 12/228:00 pmSEA - YXU
2 stops9h 46mAir Canada
lun. 12/295:40 pmYXU - SEA
1 stop7h 36mAir Canada
Deal found 9/16$605
This Mytrip deal was found by Cheapflights users on 9/16. 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.
vie. 10/3110:55 pmSEA - YXU
3 stops42h 17mWestJet
vie. 11/78:10 pmYXU - SEA
2 stops17h 13mWestJet
Deal found 9/16$683
This Mytrip deal was found by Cheapflights users on 9/16. 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.
vie. 10/3110:55 pmSEA - YXU
3 stops42h 17mMultiple Airlines
vie. 11/78:10 pmYXU - SEA
3 stops41h 13mMultiple Airlines
Deal found 9/16$695
This United Airlines deal was found by Cheapflights users on 9/16. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 12/225:02 amSEA - YXU
2 stops13h 19mUnited Airlines
lun. 12/295:45 amYXU - SEA
3 stops18h 32mUnited Airlines
Deal found 9/16$1,487

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 septiembre 17, 2025.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Seattle

Fly to

London

Route

Depart

Return

Price

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

vie. 10/31

8:00 pm-5:05 pm

2 stops18h 05m

London

vie. 11/7

5:40 pm-10:16 pm

1 stop7h 36m

$405

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

lun. 12/22

8:00 pm-8:46 am

2 stops9h 46m

London

lun. 12/29

5:40 pm-10:16 pm

1 stop7h 36m

$605

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

vie. 10/31

10:55 pm-8:12 pm

3 stops42h 17m

London

vie. 11/7

8:10 pm-10:23 am

2 stops17h 13m

$683

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

vie. 10/31

10:55 pm-8:12 pm

3 stops42h 17m

London

vie. 11/7

8:10 pm-10:23 am

3 stops41h 13m

$695

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

lun. 12/22

5:02 am-9:21 pm

2 stops13h 19m

London

lun. 12/29

5:45 am-9:17 pm

3 stops18h 32m

$1,487

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/16

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 septiembre 17, 2025.
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
10,000 reviews

Comfort

7.1

Crew

7.8

Food

6.3

Overall

7.1

Entertainment

6.8

Boarding

7.3

Reviews

1 / 20
10.0
Excellent

janet,Sep 2025

YOW - YYZ

Really appreciated the leg room despite purchasing an economy ticket. Appreciated the extra complimentary wine. Nice touch. Was given immediate support without asking at check in, at the machine!! Ottawa's boarding was very organized with distinct rows in waiting room. Allowed for the main hall to not be blocked by people waiting to board.
Air Canada
7.1
Good
10,000 reviews
Air Canada
7.1
Good
10,000 reviews

Comfort

7.1

Crew

7.8

Food

6.3

Overall

7.1

Entertainment

6.8

Boarding

7.3

Reviews

1 / 20
10.0
Excellent

janet,Sep 2025

YOW - YYZ

Really appreciated the leg room despite purchasing an economy ticket. Appreciated the extra complimentary wine. Nice touch. Was given immediate support without asking at check in, at the machine!! Ottawa's boarding was very organized with distinct rows in waiting room. Allowed for the main hall to not be blocked by people waiting to board.

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 $405, Air Canada can have you in London, Ontario from Seattle in 18h 05m. There are 2000 mi between Seattle and London, Ontario.

  • 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 $244.

  • 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?

Book flights to London if you plan to visit one of these locations
Grand Bend

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Alternative routes for Seattle to London

See prices for flight routes from nearby airports that may be better suited for you.
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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 septiembre 17, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$244Average$681FlexibilityNo cancel feeOn-time67%

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