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Cheap flights from London, ON to Seattle from C$ 339

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 23/7. Fares are subject to change and may not be available on all flights or dates of travel.
YXU — SEA
12 Jul — 19 Jul1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from London to Seattle

Enter your travel dates to find the best prices.

Cheapest flights from London to Seattle
Explore the most affordable flight options available from London to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 12 June 2026.

Wed 4/113:25 p.m.
YXU
-
SEA
1 stop8h 29m
Air Canada
Mon 7/1210:10 a.m.
SEA
-
YXU
2 stops19h 56m
Air Canada
Deal found 9/6C$ 602
Fri 16/105:55 p.m.
YXU
-
SEA
1 stop18h 45m
WestJet
Tue 20/107:35 p.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Deal found 11/6C$ 633
Wed 4/118:00 p.m.
YXU
-
SEA
1 stop20h 20m
WestJet
Sun 6/123:10 p.m.
SEA
-
YXU
1 stop24h 05m
WestJet
Deal found 9/6C$ 666
Fri 16/103:30 p.m.
YXU
-
SEA
2 stops10h 12m
Air Canada
Tue 20/105:40 a.m.
SEA
-
YXU
2 stops13h 00m
Air Canada
Deal found 11/6C$ 676
Sun 1/113:25 p.m.
YXU
-
SEA
1 stop8h 29m
United Airlines
Mon 7/1210:40 p.m.
SEA
-
YXU
2 stops13h 26m
United Airlines
Deal found 9/6C$ 677
Mon 2/118:00 p.m.
YXU
-
SEA
1 stop20h 20m
WestJet
Tue 8/123:10 p.m.
SEA
-
YXU
1 stop24h 05m
WestJet
Deal found 9/6C$ 683
Wed 4/115:45 a.m.
YXU
-
SEA
2 stops11h 33m
United Airlines
Tue 8/126:51 p.m.
SEA
-
YXU
2 stops11h 15m
United Airlines
Deal found 9/6C$ 686
Thu 5/118:00 p.m.
YXU
-
SEA
1 stop20h 20m
WestJet
Tue 8/123:10 p.m.
SEA
-
YXU
1 stop24h 05m
WestJet
Deal found 9/6C$ 697
Sun 1/113:25 p.m.
YXU
-
SEA
1 stop8h 29m
United Airlines
Thu 10/127:45 a.m.
SEA
-
YXU
1 stop11h 01m
United Airlines
Deal found 9/6C$ 728
Wed 7/106:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Sat 10/107:35 p.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Deal found 7/6C$ 739
Wed 7/103:30 p.m.
YXU
-
SEA
1 stop8h 34m
Air Canada
Sat 10/105:40 a.m.
SEA
-
YXU
2 stops13h 00m
Air Canada
Deal found 7/6C$ 765

Find flight deals from London to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from London (YXU) to Seattle (SEA). 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 12 June 2026.

Round-trip from

C$ 602

One-way from

C$ 339
WestJet
  • WestJet
  • 3/11-7/12
  • 2 total stops
  • 44h 25m total
  • London to Seattle
Search Deals
Air Canada
  • Air Canada
  • 23/7
  • 1 total stop
  • 8h 37m total
  • London to Seattle
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from London to Seattle 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 629,999 searches. Data last updated 12 June 2026.
Use the filters below to find and compare flights from London to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 16/10

5:55 p.m.-9:40 a.m.

1 stop18h 45m

Seattle/Tacoma Intl

Tue 20/10

7:35 p.m.-5:20 a.m.

1 stop6h 45m

C$ 633
Quickest round-trip

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 16/10

3:30 p.m.-9:04 p.m.

1 stop8h 34m

Seattle/Tacoma Intl

Tue 20/10

5:40 a.m.-9:40 p.m.

2 stops13h 00m

C$ 676

LondonSeattle

YXU - SEA

YXUSEA

London

Wed 4/11

3:25 p.m.-8:54 p.m.

1 stop8h 29m

Seattle/Tacoma Intl

Fri 4/12

9:02 a.m.-9:06 a.m.

2 stops21h 04m

C$ 677

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 2/11

3:25 p.m.-8:54 p.m.

1 stop8h 29m

Seattle/Tacoma Intl

Mon 7/12

10:45 p.m.-9:46 p.m.

2 stops20h 01m

C$ 677

LondonSeattle

YXU - SEA

YXUSEA

London

Sat 7/11

3:25 p.m.-8:54 p.m.

1 stop8h 29m

Seattle/Tacoma Intl

Fri 4/12

10:45 p.m.-3:06 p.m.

2 stops13h 21m

C$ 677
Cheapest one-way
Quickest one-way

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 23/7

3:30 p.m.-10:42 p.m.

2 stops10h 12m

C$ 359

LondonSeattle

YXU - SEA

YXUSEA

London

Sun 12/7

5:55 p.m.-10:39 a.m.

3 stops43h 44m

C$ 581

LondonSeattle

YXU - SEA

YXUSEA

London

Sun 12/7

9:10 p.m.-9:18 p.m.

2 stops27h 08m

C$ 582

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 23/7

6:10 a.m.-4:27 p.m.

3 stops13h 17m

C$ 711

LondonSeattle

YXU - SEA

YXUSEA

London

Sun 12/7

6:10 a.m.-9:40 a.m.

1 stop30h 30m

C$ 782

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/6

Sorted by cheapest first

Best time to book a flight from London to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from London 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 London to Seattle

What’s the top layover airport for flights from London, Ontario to Seattle?

Share of one-stop round-trip flights from London, Ontario to Seattle chosen by Cheapflights users in the past 12 months, using the same layover each way.

Calgary (YYC) – chosen by Cheapflights users on 75% of one-stop itineraries from London, Ontario to Seattle on Cheapflights.

What’s the cheapest layover airport for flights from London, Ontario to Seattle?

Average round-trip fare for 1-stop flights from London, Ontario to Seattle, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Calgary (YYC) is the most affordable 1-stop option, with an average round-trip price of C$ 396.

What’s the fastest layover option from London, Ontario to Seattle?

Shortest average travel time for 1-stop one-way flights from London, Ontario to Seattle, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Toronto (YYZ) have the shortest average one-way travel time for 1-stop routes: 7h 20m.

Which airport typically offers the quickest layover for flights from London, Ontario to Seattle?

Average layover duration for 1-stop one-way flights from London, Ontario to Seattle, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Toronto (YYZ) offer the fastest connection on this route, with an average layover time of 1h 29m.

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated 12 June 2026.
Read through reviews of airlines operating flights from London to Seattle, such as WestJet. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
WestJet
7.2
Good
3,357 reviews
Check prices

Boarding

7.4

Comfort

7.0

Entertainment

6.1

Crew

7.9

Food

6.2

Overall

7.2

Reviews

1 / 20
6.0
Good

Deb,Jan 2025

YYZ - YYC

Boarding went smoothly, you didn't accept debit card for food on flight
WestJet
7.2
Good
3,357 reviews
WestJet
7.2
Good
3,357 reviews
Check prices

Boarding

7.4

Comfort

7.0

Entertainment

6.1

Crew

7.9

Food

6.2

Overall

7.2

Reviews

1 / 20
6.0
Good

Deb,Jan 2025

YYZ - YYC

Boarding went smoothly, you didn't accept debit card for food on flight

Related info for your journey

Find useful and relevant information for your journey from London to Seattle. 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 London, Ontario to Seattle?

    Departing from London, Ontario to Seattle will take you 8h 34m. The distance between London, Ontario and Seattle is about 3219 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    According to our current data, WestJet (C$ 275), offers the cheapest pricing from London, Ontario to Seattle.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from London to Seattle 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

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Kent
Leavenworth
Mukilteo
Tacoma
Renton
Cashmere
Tukwila
Olympia
Marysville
Kirkland

Browse thousands of different options on Cheapflights for your next trip

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Top airline flying from London to Seattle

Discover the top airline that operate flights from London to Seattle. 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 629,999 searches. Data last updated 12 June 2026.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapestC$ 275AverageC$ 419FlexibilityNo cancel feeOn-time60%
Search WestJet flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from London to Seattle?

900+ travel sites are searched through when a user searches for a flight using Cheapflights. From the search interface, users can use filters to choose airlines, airports, flight times, cabin classes and more to their preference. Book your flight to Seattle from London today with Cheapflights!

Why should you use Cheapflights to find cheap flight tickets from London to Seattle?

Cheapflights helps you find that perfect flight to Seattle from London by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from London to Seattle with no change fees?

Certainly. Search results for flights to Seattle from London shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from London to Seattle become cheaper?

Yes, Cheapflights offers price alerts on London to Seattle flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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