$425+ 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 10/9. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
Sep 26 — Oct 31
Round-trip
1 adult, Economy
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Cheapest flights from Seattle to LondonExplore 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 August 27, 2026.
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 August 27, 2026.
This Vliegwinkel deal was found by Cheapflights users on 8/25. 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 Vliegwinkel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/97:35 pm -
1 stop6h 45m
Fri 10/165:55 pm -
1 stop18h 45m
Deal found 8/25![WestJet logo]()
$425
This oojo deal was found by Cheapflights users on 8/25. 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 10/87:35 pm -
1 stop6h 45m
Tue 10/136:10 am -
1 stop15h 35m
Deal found 8/25![WestJet logo]()
$446
This Trip.com deal was found by Cheapflights users on 8/27. 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 10/117:35 pm -
1 stop6h 45m
Sun 10/186:10 am -
1 stop15h 35m
Deal found 8/27![WestJet logo]()
$466
This Trip.com deal was found by Cheapflights users on 8/25. 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.
Fri 10/97:35 pm -
1 stop6h 45m
Fri 10/1610:05 am -
2 stops11h 27m
Deal found 8/25![Multiple Airlines logo]()
$501
This Kiwi.com deal was found by Cheapflights users on 8/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/1110:30 am -
1 stop15h 50m
Sun 10/186:10 am -
2 stops29h 10m
Deal found 8/27![Multiple Airlines logo]()
$551
This WestJet deal was found by Cheapflights users on 8/26. 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.
Tue 10/207:35 pm -
1 stop6h 45m
Sat 10/246:10 am -
1 stop15h 35m
Deal found 8/26![WestJet logo]()
$614
This oojo deal was found by Cheapflights users on 8/25. 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 10/87:35 pm -
1 stop6h 45m
Tue 10/136:10 am -
2 stops9h 46m
Deal found 8/25![Multiple Airlines logo]()
$674
Best flights from Seattle to LondonDiscover 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 August 27, 2026.
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 August 27, 2026.
This Trip.com deal was found by Cheapflights users on 8/27. 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 10/117:35 pm -
1 stop6h 45m
Sun 10/186:10 am -
1 stop15h 35m
Deal found 8/27![WestJet logo]()
$466
This Mytrip deal was found by Cheapflights users on 8/25. 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.
Fri 10/95:50 am -
3 stops20h 30m
Fri 10/166:10 am -
1 stop15h 35m
Deal found 8/25![Multiple Airlines logo]()
$543
This Air Canada deal was found by Cheapflights users on 8/25. 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 10/83:00 pm -
2 stops15h 20m
Tue 10/135:40 am -
2 stops11h 42m
Deal found 8/25![Air Canada logo]()
$708
This United Airlines deal was found by Cheapflights users on 8/26. 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.
Tue 10/203:18 pm -
2 stops15h 02m
Sat 10/245:40 am -
2 stops20h 46m
Deal found 8/26![United Airlines logo]()
$765
This Kiwi.com deal was found by Cheapflights users on 8/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/1110:30 am -
1 stop15h 50m
Sun 10/186:10 am -
2 stops29h 10m
Deal found 8/27![Multiple Airlines logo]()
$551
This WestJet deal was found by Cheapflights users on 8/24. 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 10/87:35 pm -
1 stop6h 45m
Thu 10/156:10 am -
1 stop15h 35m
Deal found 8/24![WestJet logo]()
$615
This WestJet deal was found by Cheapflights users on 8/24. 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.
Tue 10/207:35 pm -
1 stop6h 45m
Sat 10/246:10 am -
1 stop15h 35m
Deal found 8/24![WestJet logo]()
$615
This oojo deal was found by Cheapflights users on 8/22. 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 10/87:35 pm -
1 stop6h 45m
Tue 10/136:10 am -
2 stops9h 46m
Deal found 8/22![Multiple Airlines logo]()
$674
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 August 27, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $425 (Vliegwinkel) |
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 7,457,451 searches. Data last updated August 27, 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
Cheapest round-trip
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Sun 10/11
7:35 pm-5:20 am
1 stop6h 45m
London
Sun 10/18
6:10 am-6:45 pm
1 stop15h 35m
$466
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Fri 10/9
5:50 am-5:20 am
3 stops20h 30m
London
Fri 10/16
6:10 am-6:45 pm
1 stop15h 35m
$543
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Sun 10/11
10:30 am-5:20 am
1 stop15h 50m
London
Sun 10/18
6:10 am-8:20 am
2 stops29h 10m
$551
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Thu 10/8
7:35 pm-5:20 am
1 stop6h 45m
London
Thu 10/15
6:10 am-6:45 pm
1 stop15h 35m
$615
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Tue 10/20
7:35 pm-5:20 am
1 stop6h 45m
London
Sat 10/24
6:10 am-6:45 pm
1 stop15h 35m
$615
Quickest round-trip
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Thu 10/8
7:35 pm-5:20 am
1 stop6h 45m
London
Tue 10/13
6:10 am-12:56 pm
2 stops9h 46m
$674
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Thu 10/8
3:00 pm-9:20 am
2 stops15h 20m
London
Tue 10/13
5:40 am-2:22 pm
2 stops11h 42m
$708
SeattleLondon
SEA Seattle/Tacoma Intl - YXU London
SEAYXU
Seattle/Tacoma Intl
Tue 10/20
3:18 pm-9:20 am
2 stops15h 02m
London
Sat 10/24
5:40 am-11:26 pm
2 stops20h 46m
$765
Sorted by cheapest first
- 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.
SEA-YXU
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.
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