What is the cheapest airline that flies from Seattle/Tacoma Intl to London?

WestJet is the most popular carrier operating from Seattle/Tacoma Intl to London

What airlines fly to London, Ontario?

Alaska Airlines, Air Canada and WestJet are the top three most popular airlines that fly to London, Ontario from Seattle according to our data. Alaska Airlines is the first choice among our users, with 52% of people opting to fly with this airline when traveling to London, Ontario. Keep in mind that there are 5 different airlines that fly to London, Ontario on a routine basis, so you have a few additional options to choose from.

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?

There is 1 operator available for flights from Seattle/Tacoma Intl Airport to London Airport as of August 2025.

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.

$176 Cheap Flights from Seattle to London, Ontario (SEA-YXU) in 2025

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Find the cheapest flights from Seattle to London (SEA-YXU)

Round-trip

One-way

Cheap round-trip flights

7:55 am - 5:12 amSEA-YXU

18h 17m2 stops

8:00 pm - 12:59 pmYXU-SEA

19h 59m1 stop

$391

Find Deal

Sun, Oct 5 - Sun, Oct 12

8:06 am - 5:12 amSEA-YXU

18h 06m1 stop

6:00 am - 12:59 pmYXU-SEA

9h 59m1 stop

$451

Find Deal

Sun, Oct 5 - Sun, Oct 12

12:37 pm - 5:12 amSEA-YXU

13h 35m2 stops

8:00 pm - 7:14 pmYXU-SEA

26h 14m1 stop

$461

Find Deal

Mon, Oct 6 - Fri, Oct 10

12:36 pm - 5:12 amSEA-YXU

13h 36m2 stops

8:00 pm - 7:15 amYXU-SEA

14h 15m1 stop

$471

Find Deal

Mon, Sep 22 - Fri, Sep 26

7:15 pm - 9:19 amSEA-YXU

11h 04m2 stops

6:10 am - 2:16 pmYXU-SEA

11h 06m2 stops

$503Air Canada

Find Deal

Mon, Sep 22 - Fri, Sep 26

9:15 pm - 5:12 amSEA-YXU

28h 57m1 stop

8:00 pm - 7:15 amYXU-SEA

14h 15m1 stop

$527

Find Deal

Mon, Sep 22 - Fri, Sep 26

3:36 pm - 5:12 amSEA-YXU

10h 36m1 stop

8:00 pm - 7:14 pmYXU-SEA

26h 14m1 stop

$601

Find Deal

Mon, Oct 6 - Fri, Oct 10

10:55 pm - 7:07 pmSEA-YXU

17h 12m2 stops

8:00 pm - 12:35 pmYXU-SEA

43h 35m3 stops

$611WestJet

Find Deal

Mon, Sep 22 - Fri, Sep 26

10:55 pm - 7:07 pmSEA-YXU

17h 12m3 stops

8:00 pm - 12:35 pmYXU-SEA

43h 35m3 stops

$635WestJet

Find Deal

Mon, Sep 22 - Fri, Sep 26

10:55 pm - 7:07 pmSEA-YXU

17h 12m3 stops

8:00 pm - 12:33 pmYXU-SEA

43h 33m2 stops

$693WestJet

Find Deal

Mon, Oct 6 - Fri, Oct 10

WestJet flights from Seattle to London, Ontario

Our best WestJet deals on Seattle to London, Ontario flight tickets

WestJet

Sep 22

SEA10:55 pmSeattle/Tacoma Intl

17h 12m

2 stops

YXU7:07 pmLondon

Sep 26

YXU8:00 pmLondon

43h 35m

3 stops

SEA12:35 pmSeattle/Tacoma Intl

$611

Find similar

WestJet

Sep 22

SEA10:55 pmSeattle/Tacoma Intl

17h 12m

3 stops

YXU7:07 pmLondon

Sep 26

YXU8:00 pmLondon

43h 35m

3 stops

SEA12:35 pmSeattle/Tacoma Intl

$635

Find similar

WestJet

Oct 6

SEA10:55 pmSeattle/Tacoma Intl

17h 12m

3 stops

YXU7:07 pmLondon

Oct 10

YXU8:00 pmLondon

43h 33m

2 stops

SEA12:33 pmSeattle/Tacoma Intl

$693

Find similar

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 10/5

7:55 am-5:12 am

2 stops18h 17m

London

Sun 10/12

8:00 pm-12:59 pm

1 stop19h 59m

$391

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 10/5

8:06 am-5:12 am

1 stop18h 06m

London

Sun 10/12

6:00 am-12:59 pm

1 stop9h 59m

$451

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 10/6

12:37 pm-5:12 am

2 stops13h 35m

London

Fri 10/10

8:00 pm-7:14 pm

1 stop26h 14m

$461

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 9/22

12:36 pm-5:12 am

2 stops13h 36m

London

Fri 9/26

8:00 pm-7:15 am

1 stop14h 15m

$471

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 9/22

7:15 pm-9:19 am

2 stops11h 04m

London

Fri 9/26

6:10 am-2:16 pm

2 stops11h 06m

$503

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 9/22

9:15 pm-5:12 am

1 stop28h 57m

London

Fri 9/26

8:00 pm-7:15 am

1 stop14h 15m

$527

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 10/6

3:36 pm-5:12 am

1 stop10h 36m

London

Fri 10/10

8:00 pm-7:14 pm

1 stop26h 14m

$601

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 9/22

10:55 pm-7:07 pm

2 stops17h 12m

London

Fri 9/26

8:00 pm-12:35 pm

3 stops43h 35m

$611

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 9/22

10:55 pm-7:07 pm

3 stops17h 12m

London

Fri 9/26

8:00 pm-12:35 pm

3 stops43h 35m

$635

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 10/6

10:55 pm-7:07 pm

3 stops17h 12m

London

Fri 10/10

8:00 pm-12:33 pm

2 stops43h 33m

$693

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 13 resultsSorted by cheapest first

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

Prices

Airlines

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 12% 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.

Search flight deals

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 36m.
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?
There is 1 operator available for flights from Seattle/Tacoma Intl Airport to London Airport as of August 2025.
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?
Based on momondo bookings for this flight route, the most popular airline on flight routes from Seattle to London, Ontario is Air Canada (100% of total bookings).

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 Canada	PriceFrom $244	Free Cancellation	Rating 7.1 10,000 reviews		Search Air Canada flights

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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Find better results for your trip to Canada

Airports servicing Ontario

Popular cities in Canada

Flights to Torontofrom $93

Flights to Vancouverfrom $79

Flights to Montrealfrom $181

Flights to Calgaryfrom $145

Flights to Ottawafrom $222

Flights to Halifaxfrom $139

Flights to Winnipegfrom $170

Flights to Québec Cityfrom $142

Flights to Saskatoonfrom $146

Flights to Kelownafrom $175

Flights to St. John'sfrom $261

Flights to Reginafrom $224

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Flights from Seattle/Tacoma Intl to Ontario

Cheap flights from Seattle to London from $391

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 10/5. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

Big names and deals

Big names and deals

Filter for what you want

Filter for what you want

Trusted and free

Trusted and free

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Price Alerts

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WestJet flights from Seattle to London, Ontario

Our best WestJet deals on Seattle to London, Ontario flight tickets

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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?

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

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

You could potentially save up to 12% on your flight if you consider stops on a Seattle to London, Ontario flight.

What is the cheapest airline that flies from Seattle/Tacoma Intl to London?

WestJet is the most popular carrier operating from Seattle/Tacoma Intl to London

What airlines fly to London, Ontario?

When to book flights from Seattle to London, Ontario

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

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

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

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?

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

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

Traveling to a place near London?

Why use momondo?

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

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

How can momondo help me find flights 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?

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.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to Canada

Airports servicing Ontario