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Cheap flights from Seattle to London from $517

This is the cheapest round-trip flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to London departing on 11/23. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Cheap round-trip flights

Enter your travel dates to find the best prices.
WestJet Logo
3:10 pm - 7:12 pmSEA-YXU
25h 02m1 stop
WestJet Logo
8:10 pm - 2:20 pmYXU-SEA
21h 10m1 stop
$517WestJet
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Sun, Nov 23 - Sun, Nov 30
Air Canada Logo
5:50 am - 9:21 pmSEA-YXU
12h 31m2 stops
Air Canada Logo
5:40 pm - 10:16 pmYXU-SEA
7h 36m1 stop
$565Air Canada
Find Deal
Tue, Dec 16 - Mon, Dec 22
WestJet Logo
11:55 am - 7:12 pmSEA-YXU
52h 17m2 stops
WestJet Logo
8:10 pm - 2:20 pmYXU-SEA
21h 10m1 stop
$572WestJet
Find Deal
Sun, Nov 23 - Sun, Nov 30
Air Canada Logo
8:10 am - 9:21 pmSEA-YXU
10h 11m1 stop
Air Canada Logo
5:40 pm - 10:16 pmYXU-SEA
7h 36m1 stop
$596Air Canada
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Tue, Dec 16 - Mon, Dec 22
United Airlines Logo
11:30 pm - 5:05 pmSEA-YXU
14h 35m2 stops
United Airlines Logo
5:40 pm - 10:16 pmYXU-SEA
7h 36m1 stop
$621United Airlines
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Sat, Nov 22 - Sat, Nov 29
United Airlines Logo
8:10 am - 9:21 pmSEA-YXU
10h 11m1 stop
United Airlines Logo
5:40 pm - 10:16 pmYXU-SEA
7h 36m1 stop
$634United Airlines
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Sat, Nov 22 - Sat, Nov 29
Multiple Airlines Logo
3:12 pm - 6:34 amSEA-YXU
12h 22m2 stops
Multiple Airlines Logo
8:10 pm - 10:04 amYXU-SEA
16h 54m2 stops
$680Multiple Airlines
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Tue, Dec 16 - Mon, Dec 22
United Airlines Logo
11:30 pm - 5:05 pmSEA-YXU
14h 35m2 stops
United Airlines Logo
5:15 am - 12:59 amYXU-SEA
22h 44m2 stops
$760United Airlines
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Sat, Nov 22 - Sat, Nov 29
WestJet Logo
11:55 am - 7:12 pmSEA-YXU
28h 17m2 stops
WestJet Logo
8:10 pm - 10:22 amYXU-SEA
17h 12m2 stops
$769WestJet
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Sun, Nov 23 - Sun, Nov 30
United Airlines Logo
12:10 am - 5:05 pmSEA-YXU
13h 55m2 stops
United Airlines Logo
5:15 am - 10:21 pmYXU-SEA
20h 06m2 stops
$770United Airlines
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Sat, Nov 22 - Sun, Nov 30

WestJet flights from Seattle to London, Ontario

Our best WestJet deals on Seattle to London, Ontario flight tickets
WestJet
Nov 23
SEA3:10 pmSeattle/Tacoma Intl
25h 02m
1 stop
YXU7:12 pmLondon
Nov 30
YXU8:10 pmLondon
21h 10m
1 stop
SEA2:20 pmSeattle/Tacoma Intl
$517
Find similar
WestJet
Nov 23
SEA11:55 amSeattle/Tacoma Intl
52h 17m
2 stops
YXU7:12 pmLondon
Nov 30
YXU8:10 pmLondon
21h 10m
1 stop
SEA2:20 pmSeattle/Tacoma Intl
$572
Find similar
WestJet
Nov 23
SEA11:55 amSeattle/Tacoma Intl
28h 17m
2 stops
YXU7:12 pmLondon
Nov 30
YXU8:10 pmLondon
17h 12m
2 stops
SEA10:22 amSeattle/Tacoma Intl
$769
Find similar

United Airlines flights from Seattle to London, Ontario

Our best United Airlines deals on Seattle to London, Ontario flight tickets
United Airlines
Nov 22
SEA11:30 pmSeattle/Tacoma Intl
14h 35m
2 stops
YXU5:05 pmLondon
Nov 29
YXU5:40 pmLondon
7h 36m
1 stop
SEA10:16 pmSeattle/Tacoma Intl
$621
Find similar
United Airlines
Nov 22
SEA8:10 amSeattle/Tacoma Intl
10h 11m
1 stop
YXU9:21 pmLondon
Nov 29
YXU5:40 pmLondon
7h 36m
1 stop
SEA10:16 pmSeattle/Tacoma Intl
$634
Find similar
United Airlines
Nov 22
SEA11:30 pmSeattle/Tacoma Intl
14h 35m
2 stops
YXU5:05 pmLondon
Nov 29
YXU5:15 amLondon
22h 44m
2 stops
SEA12:59 amSeattle/Tacoma Intl
$760
Find similar

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 October 9, 2025.
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

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 11/23

3:10 pm-7:12 pm

1 stop25h 02m

London

Sun 11/30

8:10 pm-2:20 pm

1 stop21h 10m

$517

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 12/16

5:50 am-9:21 pm

2 stops12h 31m

London

Mon 12/22

5:40 pm-10:16 pm

1 stop7h 36m

$565

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 11/23

11:55 am-7:12 pm

2 stops52h 17m

London

Sun 11/30

8:10 pm-2:20 pm

1 stop21h 10m

$572

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 12/16

8:10 am-9:21 pm

1 stop10h 11m

London

Mon 12/22

5:40 pm-10:16 pm

1 stop7h 36m

$596

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 11/22

11:30 pm-5:05 pm

2 stops14h 35m

London

Sat 11/29

5:40 pm-10:16 pm

1 stop7h 36m

$621

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 11/22

8:10 am-9:21 pm

1 stop10h 11m

London

Sat 11/29

5:40 pm-10:16 pm

1 stop7h 36m

$634

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Tue 12/16

3:12 pm-6:34 am

2 stops12h 22m

London

Mon 12/22

8:10 pm-10:04 am

2 stops16h 54m

$680

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 11/22

11:30 pm-5:05 pm

2 stops14h 35m

London

Sat 11/29

5:15 am-12:59 am

2 stops22h 44m

$760

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 11/23

11:55 am-7:12 pm

2 stops28h 17m

London

Sun 11/30

8:10 pm-10:22 am

2 stops17h 12m

$769

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 11/22

12:10 am-5:05 pm

2 stops13h 55m

London

Sun 11/30

5:15 am-10:21 pm

2 stops20h 06m

$770

Flights are sorted by cheapest round-trip flights first.

Sorted by cheapest first

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

What is the cheapest day to depart on your flight to London, Ontario?

According to our data, Thursday is the cheapest day to fly to London, Ontario from Seattle. The lowest ticket price found for a Thursday departure recently was $244. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. Be sure to avoid booking your departure on a Tuesday as prices are generally higher than usual. According to our data, the average ticket price to London, Ontario on Tuesday is $680.

What is the cheapest time of day to depart on your flight to London, Ontario?

In the evening is the cheapest time of day to fly from Seattle to London, Ontario when you can find flight prices for as low as $385. Flying to London, Ontario in the evening is an ideal time because this is during off-peak travel hours. In the morning is when there is more demand to fly to London, Ontario, so prices are often more expensive at around $495 per ticket.

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

You could potentially save up to 37% 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

Direct flights

None
There are no direct flights from Seattle to London, Ontario. There are no popular flight routes from Seattle to London, Ontario.
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  • 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 10h 11m.

  • 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 many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London Airport?

  • 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.

  • What is the most popular airline from Seattle to London, Ontario?

Best airlines flying from Seattle to London, Ontario

Compare and see reviews for airlines that fly from Seattle to London, Ontario with momondo
Airline
Rating
Free Cancellation
Price
Air CanadaPriceFrom $248Free CancellationRating
7.1
10,261 reviews
Search Air Canada flights

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

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