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Cheap flights from Seattle to London from $255

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to London departing on 6/9. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Find the cheapest flights from Seattle to London

Cheap round-trip flights

Enter your travel dates to find the best prices.
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
5:55 pm - 6:45 pm
YXU
-
SEA
27h 50m
1 stop
$374WestJet
Tue, Sep 8 - Fri, Sep 11
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
6:10 am - 6:45 pm
YXU
-
SEA
15h 35m
1 stop
$448WestJet
Wed, Sep 23 - Wed, Oct 7
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
6:10 am - 6:45 pm
YXU
-
SEA
15h 35m
1 stop
$455WestJet
Wed, Sep 23 - Wed, Oct 7
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
6:10 am - 6:45 pm
YXU
-
SEA
15h 35m
1 stop
$458WestJet
Fri, Jun 5 - Sat, Jun 13
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
5:55 pm - 6:45 pm
YXU
-
SEA
27h 50m
1 stop
$475WestJet
Tue, Sep 8 - Fri, Sep 11
Air Canada Logo
5:40 am - 9:40 pm
SEA
-
YXU
13h 00m
2 stops
Air Canada Logo
3:30 pm - 9:04 pm
YXU
-
SEA
8h 34m
1 stop
$557Air Canada
Tue, Sep 22 - Wed, Oct 7
Air Canada Logo
5:40 am - 5:43 pm
SEA
-
YXU
9h 03m
2 stops
Air Canada Logo
3:30 pm - 9:04 pm
YXU
-
SEA
8h 34m
1 stop
$571Air Canada
Tue, Sep 8 - Fri, Sep 11
WestJet Logo
7:35 pm - 5:20 am
SEA
-
YXU
6h 45m
1 stop
WestJet Logo
2:40 pm - 9:40 am
YXU
-
SEA
22h 00m
2 stops
$572WestJet
Tue, Sep 8 - Fri, Sep 11
Air Canada Logo
7:20 pm - 9:20 am
SEA
-
YXU
11h 00m
2 stops
Air Canada Logo
3:30 pm - 10:42 pm
YXU
-
SEA
10h 12m
2 stops
$577Air Canada
Tue, Sep 8 - Fri, Sep 11
Air Canada Logo
8:00 am - 9:40 pm
SEA
-
YXU
10h 40m
1 stop
Air Canada Logo
3:30 pm - 9:04 pm
YXU
-
SEA
8h 34m
1 stop
$589Air Canada
Tue, Sep 22 - Wed, Oct 7

WestJet flights from Seattle to London, Ontario

Our best WestJet deals on Seattle to London, Ontario flight tickets
WestJet
Sep 8
SEA7:35 pmSeattle/Tacoma Intl
6h 45m
1 stop
YXU5:20 amLondon
Sep 11
YXU5:55 pmLondon
27h 50m
1 stop
SEA6:45 pmSeattle/Tacoma Intl
$374
WestJet
Sep 23
SEA7:35 pmSeattle/Tacoma Intl
6h 45m
1 stop
YXU5:20 amLondon
Oct 7
YXU6:10 amLondon
15h 35m
1 stop
SEA6:45 pmSeattle/Tacoma Intl
$448
WestJet
Sep 23
SEA7:35 pmSeattle/Tacoma Intl
6h 45m
1 stop
YXU5:20 amLondon
Oct 7
YXU6:10 amLondon
15h 35m
1 stop
SEA6:45 pmSeattle/Tacoma Intl
$455

United Airlines flights from Seattle to London, Ontario

Our best United Airlines deals on Seattle to London, Ontario flight tickets
United Airlines
Jul 7
SEA8:00 amSeattle/Tacoma Intl
6h 45m
1 stop
YXU5:45 pmLondon
Jul 14
YXU3:30 pmLondon
8h 37m
1 stop
SEA9:07 pmSeattle/Tacoma Intl
$697
United Airlines
Jul 7
SEA7:00 amSeattle/Tacoma Intl
11h 40m
2 stops
YXU9:40 pmLondon
Jul 14
YXU3:30 pmLondon
8h 37m
1 stop
SEA9:07 pmSeattle/Tacoma Intl
$707
United Airlines
Jul 7
SEA5:20 pmSeattle/Tacoma Intl
13h 00m
2 stops
YXU9:20 amLondon
Jul 14
YXU10:05 amLondon
16h 05m
2 stops
SEA11:10 pmSeattle/Tacoma Intl
$722

momondo Fare Finder

 
Customize your flight search to find flights from Seattle to London, Ontario 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, momondo users made 832,500 searches. Data last updated May 23, 2026.
Use the filters below to find and compare flights from Seattle to London, Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/8

7:35 pm-5:20 am

1 stop6h 45m

London

Fri 9/11

5:55 pm-6:45 pm

1 stop27h 50m

$374

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 9/23

7:35 pm-5:20 am

1 stop6h 45m

London

Wed 10/7

6:10 am-6:45 pm

1 stop15h 35m

$448

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 9/23

7:35 pm-5:20 am

1 stop6h 45m

London

Wed 10/7

6:10 am-6:45 pm

1 stop15h 35m

$455

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Fri 6/5

7:35 pm-5:20 am

1 stop6h 45m

London

Sat 6/13

6:10 am-6:45 pm

1 stop15h 35m

$458

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/8

7:35 pm-5:20 am

1 stop6h 45m

London

Fri 9/11

5:55 pm-6:45 pm

1 stop27h 50m

$475

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/22

5:40 am-9:40 pm

2 stops13h 00m

London

Wed 10/7

3:30 pm-9:04 pm

1 stop8h 34m

$557
Quickest round-trip

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/8

5:40 am-5:43 pm

2 stops9h 03m

London

Fri 9/11

3:30 pm-9:04 pm

1 stop8h 34m

$571

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/8

7:35 pm-5:20 am

1 stop6h 45m

London

Fri 9/11

2:40 pm-9:40 am

2 stops22h 00m

$572

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/8

7:20 pm-9:20 am

2 stops11h 00m

London

Fri 9/11

3:30 pm-10:42 pm

2 stops10h 12m

$577

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 9/22

8:00 am-9:40 pm

1 stop10h 40m

London

Wed 10/7

3:30 pm-9:04 pm

1 stop8h 34m

$589

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 14 resultsSorted by cheapest first
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See travel insights to London from

How to get the cheapest flight ticket from Seattle to London, Ontario

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Can stopping save me money on Seattle to London, Ontario flights?

You could potentially save up to 66% on your flight if you consider stops on a Seattle to London, Ontario flight.

When to book flights from Seattle to London, Ontario

Are you open to changing your travel dates? Check out the ideal times to fly from Seattle to London, Ontario according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Seattle to London, Ontario (SEA to YXU) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Seattle to London, Ontario

Fastest flight time

6h 45m

Direct flights

None
The fastest flight from Seattle to London, Ontario takes 6h 45m
There are no direct flights from Seattle to London, Ontario. There are no popular flight routes from Seattle to London, Ontario.
Search flight deals

Frequently asked questions about flying from Seattle to London, Ontario

  • How far is Seattle/Tacoma Intl to London by plane?

    The straight-line distance from Seattle/Tacoma Intl to London is 1997.9 mi. By plane, this route typically takes 6h 45m.

  • When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Airport?

    Prices for flights from Seattle/Tacoma Intl Airport to London Airport are updated daily.

  • How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to London Airport.

  • What documentation or ID do you need to fly to London Airport?

    The travel and health documents you'll need for your trip to London Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

Traveling to a place near London?

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

Why use momondo?

Why should I use momondo to find a flight deal from Seattle to London?

Finding the right flight to London from Seattle is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to London quick and easy, saving you time and money.

Can I find flights from Seattle to London with flexible booking policies on momondo?

momondo does allow users to show only those flights to London from Seattle which offer a flexible booking policy as well as other useful filters and features.

How can momondo help me find flights from Seattle to London?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Seattle to London.

I’m not ready to book a flight from Seattle to London right now. Can momondo alert me if prices change?

Yes. momondo can track prices for Seattle to London flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.

An easier way to manage your London, Ontario trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
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