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Cheap flights from Seattle to London, ON from C$ 232

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 18/6. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
10 Apr — 17 Apr1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Seattle to London

Enter your travel dates to find the best prices.

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 11 March 2026.

Tue 21/43:10 p.m.
SEA
-
YXU
1 stop12h 25m
WestJet
Tue 28/45:55 p.m.
YXU
-
SEA
1 stop27h 50m
WestJet
Deal found 6/3C$ 534
Thu 21/510:30 a.m.
SEA
-
YXU
1 stop15h 50m
WestJet
Sat 30/56:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 10/3C$ 576
Wed 29/47:35 p.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Sun 3/55:55 p.m.
YXU
-
SEA
1 stop18h 45m
WestJet
Deal found 8/3C$ 581
Mon 20/411:55 a.m.
SEA
-
YXU
2 stops15h 40m
WestJet
Mon 27/46:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 8/3C$ 603
Tue 21/48:41 a.m.
SEA
-
YXU
2 stops18h 54m
Multiple Airlines
Tue 28/45:55 p.m.
YXU
-
SEA
1 stop18h 45m
Multiple Airlines
Deal found 6/3C$ 634
Mon 20/43:35 p.m.
SEA
-
YXU
1 stop12h 00m
Multiple Airlines
Mon 27/46:10 a.m.
YXU
-
SEA
1 stop15h 35m
Multiple Airlines
Deal found 8/3C$ 688
Thu 25/67:35 p.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Wed 15/76:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 9/3C$ 699
Thu 18/67:00 a.m.
SEA
-
YXU
1 stop6h 45m
WestJet
Tue 30/66:10 a.m.
YXU
-
SEA
1 stop15h 35m
WestJet
Deal found 7/3C$ 701
Thu 2/75:40 a.m.
SEA
-
YXU
2 stops8h 55m
Air Canada
Thu 9/73:30 p.m.
YXU
-
SEA
1 stop8h 37m
Air Canada
Deal found 9/3C$ 707

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 11 March 2026.

Round-trip from

C$ 534

One-way from

C$ 232
WestJet
  • WestJet
  • 21/4-28/4
  • 2 total stops
  • 40h 15m total
  • Seattle to London
Search Deals
WestJet
  • WestJet
  • 18/6
  • 1 total stop
  • 6h 45m total
  • Seattle to London
Search Deals

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 629,999 searches. Data last updated 11 March 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

Mon 20/4

11:55 a.m.-6:35 a.m.

2 stops15h 40m

London

Mon 27/4

6:10 a.m.-6:45 p.m.

1 stop15h 35m

C$ 603

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 29/4

10:30 a.m.-4:45 p.m.

1 stop27h 15m

London

Sun 3/5

6:10 a.m.-6:45 p.m.

1 stop15h 35m

C$ 623

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 21/4

8:41 a.m.-6:35 a.m.

2 stops18h 54m

London

Tue 28/4

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

1 stop18h 45m

C$ 634

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 20/4

3:35 p.m.-6:35 a.m.

1 stop12h 00m

London

Mon 27/4

6:10 a.m.-6:45 p.m.

1 stop15h 35m

C$ 688

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 25/6

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

1 stop6h 45m

London

Wed 15/7

6:10 a.m.-6:45 p.m.

1 stop15h 35m

C$ 699
Quickest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 25/6

7:20 p.m.-8:52 a.m.

2 stops10h 32m

London

Wed 15/7

3:30 p.m.-9:07 p.m.

1 stop8h 37m

C$ 701

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 29/4

8:00 p.m.-8:44 a.m.

2 stops9h 44m

London

Sun 3/5

5:40 a.m.-6:30 p.m.

2 stops15h 50m

C$ 733
Cheapest one-way
Quickest one-way

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 18/6

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

1 stop6h 45m

C$ 232

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 19/6

7:00 a.m.-4:45 p.m.

1 stop6h 45m

C$ 234

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 16/5

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

1 stop6h 45m

C$ 240

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/3

Showing 1-10 of 15 resultsSorted by cheapest first
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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, January is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of C$ 179). Flying from Seattle to London, Ontario in May is currently the most expensive (average of C$ 382). 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.

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 C$ 603, WestJet can have you in London, Ontario from Seattle in 15h 40m. The distance between Seattle and London, Ontario is about 3219 km.

  • 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, January is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of C$ 179). Flying from Seattle to London, Ontario in May is currently the most expensive (average of C$ 382). 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

Travelling to a place near London?

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

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

Need flexible booking options for your flight to London from Seattle? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

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