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$283+ 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 2/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
Jan 22 — Jan 291
Thu 1/22
Thu 1/29
1 adult, Economy
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Cheap flight deals from Seattle to London

Best flights from Seattle to London
Discover carefully curated flight deals from Seattle to London that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 23, 2025.

This Air Canada deal was found by Cheapflights users on 12/21. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/58:00 pmSEA - YXU
2 stops9h 46mAir Canada
Thu 2/125:40 pmYXU - SEA
1 stop7h 36mAir Canada
Deal found 12/21$283
This United Airlines deal was found by Cheapflights users on 12/21. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/512:57 pmSEA - YXU
3 stops25h 08mUnited Airlines
Thu 2/125:40 pmYXU - SEA
1 stop7h 36mUnited Airlines
Deal found 12/21$379
This WestJet deal was found by Cheapflights users on 12/20. 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 WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/163:10 pmSEA - YXU
1 stop12h 25mWestJet
Wed 3/188:10 pmYXU - SEA
1 stop21h 09mWestJet
Deal found 12/20$420
This Air Canada deal was found by Cheapflights users on 12/20. 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.
Mon 3/168:00 pmSEA - YXU
2 stops9h 46mAir Canada
Wed 3/185:10 amYXU - SEA
2 stops12h 51mAir Canada
Deal found 12/20$591

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 December 23, 2025.

Most accurate provider

oojo
3 stars

Most trusted provider

oojo
3 stars

Round-trip from

$283
(Air Canada)
Provider with most accurate pricing for Seattle/Tacoma Intl-London flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-London flights.
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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 December 23, 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

Thu 2/5

8:00 pm-8:46 am

2 stops9h 46m

London

Thu 2/12

5:40 pm-10:16 pm

1 stop7h 36m

$283

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 2/5

12:57 pm-5:05 pm

3 stops25h 08m

London

Thu 2/12

5:40 pm-10:16 pm

1 stop7h 36m

$379

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 3/16

3:10 pm-6:35 am

1 stop12h 25m

London

Wed 3/18

8:10 pm-2:19 pm

1 stop21h 09m

$420

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 3/16

8:00 pm-8:46 am

2 stops9h 46m

London

Wed 3/18

5:10 am-3:01 pm

2 stops12h 51m

$591

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/21

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 December.
ProviderPrice AccuracyTrust Score*
FlightHubPrice Accuracy3 starsTrust Score*1 star
oojoPrice Accuracy3 starsTrust Score*3 stars
Trip.comPrice Accuracy2 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust 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 oojo to be most consistent on Cheapflights vs. oojo Users can find the same prices on Seattle-London, Ontario flight deals on Cheapflights vs. oojo >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 oojo the most. oojo 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.

Cheapflights Insights

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

What is the cheapest month to book a flight from Seattle to London, Ontario?

Currently, March is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of $123). Flying from Seattle to London, Ontario in May is currently the most expensive (average of $272). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

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 December 23, 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
10,551 reviews

Comfort

7.1

Overall

7.1

Entertainment

6.8

Boarding

7.3

Crew

7.8

Food

6.3

Reviews

1 / 20
2.0
Mediocre

Shawna,Sep 2025

DCA - YYZ

Business class cabin was *freezing*. Landing was so hard it injured my back - no apology or explanation given
Air Canada
7.1
Good
10,551 reviews
Air Canada
7.1
Good
10,551 reviews

Comfort

7.1

Overall

7.1

Entertainment

6.8

Boarding

7.3

Crew

7.8

Food

6.3

Reviews

1 / 20
2.0
Mediocre

Shawna,Sep 2025

DCA - YYZ

Business class cabin was *freezing*. Landing was so hard it injured my back - no apology or explanation given

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 $283, Air Canada can have you in London, Ontario from Seattle in 9h 46m. 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.

  • What is the cheapest month to book a flight from Seattle to London, Ontario?

    Currently, March is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of $123). Flying from Seattle to London, Ontario in May is currently the most expensive (average of $272). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

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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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 December 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$460Average$857FlexibilityNo cancel feeOn-time67%

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