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

Which airlines fly to London, Ontario?

Alaska Airlines, WestJet and Air Canada 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 47% of people opting to fly with this airline when travelling to London, Ontario. Keep in mind that there are 3 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 old do you have to be to fly from Seattle/Tacoma Intl Airport to London Airport?

Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, 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 required for your trip to London Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at London Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

C$ 291 Cheap Flights from Seattle to London, Ontario in 2026

Find the cheapest flights from Seattle to London

Round-trip

One-way

Cheap round-trip flights

Enter your travel dates to find the best prices.

7:35 p.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

6h 45m1 stop Calgary

7:40 a.m. - 2:40 p.m.YXU London-SEA Seattle/Tacoma Intl

10h 00m1 stop Calgary

C$ 547WestJet

Fri, 23 Oct - Fri, 30 Oct

7:35 p.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

6h 45m1 stop Calgary

6:10 a.m. - 6:45 p.m.YXU London-SEA Seattle/Tacoma Intl

15h 35m1 stop Calgary

C$ 575WestJet

Tue, 20 Oct - Sat, 24 Oct

7:35 p.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

6h 45m1 stop Calgary

6:10 a.m. - 6:45 p.m.YXU London-SEA Seattle/Tacoma Intl

15h 35m1 stop Calgary

C$ 604WestJet

Tue, 20 Oct - Sat, 24 Oct

7:35 p.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

6h 45m1 stop Calgary

6:10 a.m. - 6:45 p.m.YXU London-SEA Seattle/Tacoma Intl

15h 35m1 stop Calgary

C$ 714WestJet

Tue, 20 Oct - Sat, 24 Oct

10:30 a.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

15h 50m1 stop Calgary

7:40 a.m. - 6:31 p.m.YXU London-SEA Seattle/Tacoma Intl

13h 51m2 stops Calgary Vancouver Intl

C$ 717Multiple Airlines

Fri, 23 Oct - Fri, 30 Oct

10:30 a.m. - 5:20 a.m.SEA Seattle/Tacoma Intl-YXU London

15h 50m1 stop Calgary

5:55 p.m. - 6:45 p.m.YXU London-SEA Seattle/Tacoma Intl

27h 50m1 stop Calgary

C$ 756WestJet

Sun, 4 Oct - Sun, 11 Oct

5:50 a.m. - 5:43 p.m.SEA Seattle/Tacoma Intl-YXU London

8h 53m2 stops Vancouver Intl Toronto Pearson Intl

3:25 p.m. - 9:27 a.m.YXU London-SEA Seattle/Tacoma Intl

21h 02m2 stops Toronto Pearson Intl Vancouver Intl

C$ 863Air Canada

Fri, 23 Oct - Fri, 30 Oct

7:55 a.m. - 7:40 p.m.SEA Seattle/Tacoma Intl-YXU London

8h 45m1 stop Toronto Pearson Intl

9:05 a.m. - 6:32 p.m.YXU London-SEA Seattle/Tacoma Intl

12h 27m2 stops Toronto Pearson Intl Vancouver Intl

C$ 942Air Canada

Tue, 20 Oct - Sat, 24 Oct

7:15 p.m. - 8:25 a.m.SEA Seattle/Tacoma Intl-YXU London

10h 10m2 stops Vancouver Intl Toronto Pearson Intl

9:05 a.m. - 6:32 p.m.YXU London-SEA Seattle/Tacoma Intl

12h 27m2 stops Toronto Pearson Intl Vancouver Intl

C$ 949Air Canada

Tue, 20 Oct - Sat, 24 Oct

7:55 a.m. - 7:40 p.m.SEA Seattle/Tacoma Intl-YXU London

8h 45m1 stop Toronto Pearson Intl

9:05 a.m. - 6:32 p.m.YXU London-SEA Seattle/Tacoma Intl

12h 27m2 stops Toronto Pearson Intl Vancouver Intl

C$ 1,001Air Canada

Tue, 20 Oct - Sat, 24 Oct

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United Airlines flights from Seattle to London, Ontario

Our best United Airlines deals on Seattle to London, Ontario flight tickets

United Airlines

4 Oct

SEA6:43 p.m.Seattle/Tacoma Intl

10h 42m

2 stops

YXU8:25 a.m.London

11 Oct

YXU3:30 p.m.London

8h 34m

1 stop

SEA9:04 p.m.Seattle/Tacoma Intl

C$ 1,201

United Airlines

4 Oct

SEA5:05 p.m.Seattle/Tacoma Intl

21h 38m

3 stops

YXU5:43 p.m.London

11 Oct

YXU3:30 p.m.London

8h 34m

1 stop

SEA9:04 p.m.Seattle/Tacoma Intl

C$ 1,209

United Airlines

4 Oct

SEA5:05 p.m.Seattle/Tacoma Intl

21h 38m

3 stops

YXU5:43 p.m.London

11 Oct

YXU8:20 p.m.London

18h 07m

2 stops

SEA11:27 a.m.Seattle/Tacoma Intl

C$ 1,295

WestJet flights from Seattle to London, Ontario

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

WestJet

23 Oct

SEA7:35 p.m.Seattle/Tacoma Intl

6h 45m

1 stop

YXU5:20 a.m.London

30 Oct

YXU7:40 a.m.London

10h 00m

1 stop

SEA2:40 p.m.Seattle/Tacoma Intl

C$ 547

WestJet

20 Oct

SEA7:35 p.m.Seattle/Tacoma Intl

6h 45m

1 stop

YXU5:20 a.m.London

24 Oct

YXU6:10 a.m.London

15h 35m

1 stop

SEA6:45 p.m.Seattle/Tacoma Intl

C$ 575

WestJet

20 Oct

SEA7:35 p.m.Seattle/Tacoma Intl

6h 45m

1 stop

YXU5:20 a.m.London

24 Oct

YXU6:10 a.m.London

15h 35m

1 stop

SEA6:45 p.m.Seattle/Tacoma Intl

C$ 604

momondo Fare Finder

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

Quickest round-trip

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Fri 23/10

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

1 stop6h 45m

London

Fri 30/10

7:40 a.m.-2:40 p.m.

1 stop10h 00m

C$ 547

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

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

1 stop6h 45m

London

Sat 24/10

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

1 stop15h 35m

C$ 575

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

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

1 stop6h 45m

London

Sat 24/10

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

1 stop15h 35m

C$ 604

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

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

1 stop6h 45m

London

Sat 24/10

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

1 stop15h 35m

C$ 714

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Fri 23/10

10:30 a.m.-5:20 a.m.

1 stop15h 50m

London

Fri 30/10

7:40 a.m.-6:31 p.m.

2 stops13h 51m

C$ 717

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Sun 4/10

10:30 a.m.-5:20 a.m.

1 stop15h 50m

London

Sun 11/10

5:55 p.m.-6:45 p.m.

1 stop27h 50m

C$ 756

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Fri 23/10

5:50 a.m.-5:43 p.m.

2 stops8h 53m

London

Fri 30/10

3:25 p.m.-9:27 a.m.

2 stops21h 02m

C$ 863

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

7:55 a.m.-7:40 p.m.

1 stop8h 45m

London

Sat 24/10

9:05 a.m.-6:32 p.m.

2 stops12h 27m

C$ 942

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

7:15 p.m.-8:25 a.m.

2 stops10h 10m

London

Sat 24/10

9:05 a.m.-6:32 p.m.

2 stops12h 27m

C$ 949

SeattleLondon

SEA Seattle/Tacoma Intl - YXU London

SEAYXU

Seattle/Tacoma Intl

Tue 20/10

7:55 a.m.-7:40 p.m.

1 stop8h 45m

London

Sat 24/10

9:05 a.m.-6:32 p.m.

2 stops12h 27m

C$ 1,001

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

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

You could potentially save up to 59% 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

Best price found	C$ 291
Fastest flight time	30h 10m
Direct flights	None

The best one-way flight to London, Ontario from Seattle in the past 72 hours is C$ 291. The best round-trip flight deal from Seattle to London, Ontario found on momondo in the last 72 hours is C$ 547.

The fastest flight from Seattle to London, Ontario takes 30h 10m

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?
London is 3215.2 km away from Seattle/Tacoma Intl. A reasonable flight in good conditions will take 30h 10m.
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?
Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, 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 required for your trip to London Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at London Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

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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 recognizable 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?

All flight searches from Seattle to London on momondo can be filtered to show those which offer flexible booking policies.

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

Once you have performed a search for Seattle to London flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

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

Price alerts on flights to London from Seattle are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.