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

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

Which airlines fly to Seattle?

Alaska Airlines, Air Canada and WestJet are the top three most popular airlines that fly to Seattle from London, Ontario according to our data. Alaska Airlines is the first choice among our users, with 38% of people opting to fly with this airline when travelling to Seattle. Keep in mind that there are 6 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.

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

Prices for flights from London Airport to Seattle/Tacoma Intl Airport were last updated today.

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

The number of operators available for flights from London Airport to Seattle/Tacoma Intl Airport is 3 as of December 2025.

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

What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?

The necessary travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

C$ 242 Cheap Flights from London to Seattle in 2025/26

1 adult

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Find the cheapest flights from London, Ontario to Seattle

Round-trip

One-way

Cheap round-trip flights

Enter your travel dates to find the best prices.

5:40 p.m. - 10:16 p.m.

YXU

SEA

7h 36m1 stop

8:10 a.m. - 9:21 p.m.

SEA

YXU

10h 11m2 stops

C$ 428United Airlines

Fri, 30 Jan - Fri, 6 Feb

5:10 a.m. - 9:12 p.m.

YXU

SEA

19h 02m3 stops

12:35 p.m. - 5:05 p.m.

SEA

YXU

25h 30m3 stops

C$ 437United Airlines

Fri, 30 Jan - Fri, 6 Feb

5:40 p.m. - 10:16 p.m.

YXU

SEA

7h 36m1 stop

8:10 a.m. - 9:21 p.m.

SEA

YXU

10h 11m1 stop

C$ 478United Airlines

Fri, 30 Jan - Fri, 6 Feb

5:10 a.m. - 9:12 p.m.

YXU

SEA

19h 02m2 stops

7:00 a.m. - 9:21 p.m.

SEA

YXU

11h 21m2 stops

C$ 564United Airlines

Tue, 13 Jan - Tue, 20 Jan

5:10 a.m. - 9:12 p.m.

YXU

SEA

19h 02m3 stops

12:35 p.m. - 5:05 p.m.

SEA

YXU

25h 30m3 stops

C$ 605United Airlines

Tue, 13 Jan - Tue, 20 Jan

5:40 p.m. - 10:16 p.m.

YXU

SEA

7h 36m1 stop

5:00 a.m. - 5:05 p.m.

SEA

YXU

9h 05m2 stops

C$ 681United Airlines

Tue, 13 Jan - Tue, 20 Jan

8:10 p.m. - 2:19 p.m.

YXU

SEA

21h 09m1 stop

3:10 p.m. - 6:35 a.m.

SEA

YXU

12h 25m1 stop

C$ 723WestJet

Mon, 2 Mar - Wed, 4 Mar

8:10 p.m. - 2:19 p.m.

YXU

SEA

21h 09m1 stop

3:10 p.m. - 6:35 a.m.

SEA

YXU

12h 25m1 stop

C$ 730WestJet

Mon, 2 Mar - Wed, 4 Mar

9:25 a.m. - 7:16 p.m.

YXU

SEA

12h 51m2 stops

5:50 a.m. - 9:21 p.m.

SEA

YXU

12h 31m2 stops

C$ 738Air Canada

Mon, 2 Mar - Wed, 4 Mar

9:25 a.m. - 7:16 p.m.

YXU

SEA

12h 51m2 stops

5:50 a.m. - 9:21 p.m.

SEA

YXU

12h 31m2 stops

C$ 748Air Canada

Mon, 2 Mar - Wed, 4 Mar

United Airlines flights from London, Ontario to Seattle

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

United Airlines

30 Jan

YXU5:40 p.m.London

7h 36m

1 stop

SEA10:16 p.m.Seattle/Tacoma Intl

6 Feb

SEA8:10 a.m.Seattle/Tacoma Intl

10h 11m

2 stops

YXU9:21 p.m.London

C$ 428

Find similar

United Airlines

30 Jan

YXU5:10 a.m.London

19h 02m

3 stops

SEA9:12 p.m.Seattle/Tacoma Intl

6 Feb

SEA12:35 p.m.Seattle/Tacoma Intl

25h 30m

3 stops

YXU5:05 p.m.London

C$ 437

Find similar

United Airlines

30 Jan

YXU5:40 p.m.London

7h 36m

1 stop

SEA10:16 p.m.Seattle/Tacoma Intl

6 Feb

SEA8:10 a.m.Seattle/Tacoma Intl

10h 11m

1 stop

YXU9:21 p.m.London

C$ 478

Find similar

WestJet flights from London, Ontario to Seattle

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

WestJet

2 Mar

YXU8:10 p.m.London

21h 09m

1 stop

SEA2:19 p.m.Seattle/Tacoma Intl

4 Mar

SEA3:10 p.m.Seattle/Tacoma Intl

12h 25m

1 stop

YXU6:35 a.m.London

C$ 723

Find similar

WestJet

2 Mar

YXU8:10 p.m.London

21h 09m

1 stop

SEA2:19 p.m.Seattle/Tacoma Intl

4 Mar

SEA3:10 p.m.Seattle/Tacoma Intl

12h 25m

1 stop

YXU6:35 a.m.London

C$ 730

Find similar

WestJet

13 Jan

YXU8:10 p.m.London

21h 10m

1 stop

SEA2:20 p.m.Seattle/Tacoma Intl

20 Jan

SEA3:10 p.m.Seattle/Tacoma Intl

12h 24m

1 stop

YXU6:34 a.m.London

C$ 1,473

Find similar

Fly from

Fly to

Route

Depart

Return

Price

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 30/1

5:40 p.m.-10:16 p.m.

1 stop7h 36m

Seattle/Tacoma Intl

Fri 6/2

8:10 a.m.-9:21 p.m.

2 stops10h 11m

C$ 428

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 30/1

5:10 a.m.-9:12 p.m.

3 stops19h 02m

Seattle/Tacoma Intl

Fri 6/2

12:35 p.m.-5:05 p.m.

3 stops25h 30m

C$ 437

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 30/1

5:40 p.m.-10:16 p.m.

1 stop7h 36m

Seattle/Tacoma Intl

Fri 6/2

8:10 a.m.-9:21 p.m.

1 stop10h 11m

C$ 478

LondonSeattle

YXU - SEA

YXUSEA

London

Tue 13/1

5:10 a.m.-9:12 p.m.

2 stops19h 02m

Seattle/Tacoma Intl

Tue 20/1

7:00 a.m.-9:21 p.m.

2 stops11h 21m

C$ 564

LondonSeattle

YXU - SEA

YXUSEA

London

Tue 13/1

5:10 a.m.-9:12 p.m.

3 stops19h 02m

Seattle/Tacoma Intl

Tue 20/1

12:35 p.m.-5:05 p.m.

3 stops25h 30m

C$ 605

LondonSeattle

YXU - SEA

YXUSEA

London

Tue 13/1

5:40 p.m.-10:16 p.m.

1 stop7h 36m

Seattle/Tacoma Intl

Tue 20/1

5:00 a.m.-5:05 p.m.

2 stops9h 05m

C$ 681

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 2/3

8:10 p.m.-2:19 p.m.

1 stop21h 09m

Seattle/Tacoma Intl

Wed 4/3

3:10 p.m.-6:35 a.m.

1 stop12h 25m

C$ 723

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 2/3

8:10 p.m.-2:19 p.m.

1 stop21h 09m

Seattle/Tacoma Intl

Wed 4/3

3:10 p.m.-6:35 a.m.

1 stop12h 25m

C$ 730

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 2/3

9:25 a.m.-7:16 p.m.

2 stops12h 51m

Seattle/Tacoma Intl

Wed 4/3

5:50 a.m.-9:21 p.m.

2 stops12h 31m

C$ 738

LondonSeattle

YXU - SEA

YXUSEA

London

Mon 2/3

9:25 a.m.-7:16 p.m.

2 stops12h 51m

Seattle/Tacoma Intl

Wed 4/3

5:50 a.m.-9:21 p.m.

2 stops12h 31m

C$ 748

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 12 resultsSorted by cheapest first

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

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 Seattle?

Our data shows that Friday is the least expensive day to fly to Seattle. Tickets to fly out on this day can be as low as C$ 369. If your travel schedule is flexible, try to avoid departing on a Saturday because tickets tend to average around C$ 703. These prices are subject to change though, so be sure to set up a Price Alert for flights to Seattle.

What is the cheapest time of day to depart on your flight to Seattle?

Our most recent data shows that the best time of day to fly to Seattle is in the afternoon. Flights from London, Ontario to Seattle during this time can be as low as C$ 556. Flights in the morning are often more expensive with an average ticket price of C$ 564.

When to book flights from London, Ontario to Seattle

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

Estimated round-trip price

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

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

Fastest flight time	7h 36m
Direct flights	None

The fastest flight from London, Ontario to Seattle takes 7h 36m

There are no direct flights from London, Ontario to Seattle. There are no popular flight routes from London, Ontario to Seattle.

Search flight deals

How far is London to Seattle/Tacoma Intl by plane?
The distance between London and Seattle/Tacoma Intl is about 3215.2 km. By plane, this route typically takes 7h 36m.
When did momondo last update prices for flights from London Airport to Seattle/Tacoma Intl Airport?
Prices for flights from London Airport to Seattle/Tacoma Intl Airport were last updated today.
How many operators does momondo search for flights from London Airport to Seattle/Tacoma Intl Airport?
The number of operators available for flights from London Airport to Seattle/Tacoma Intl Airport is 3 as of December 2025.
How old do you have to be to fly from London Airport to Seattle/Tacoma Intl 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 London Airport to Seattle/Tacoma Intl Airport.
What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?
The necessary travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.
What is the most popular airline from London, Ontario to Seattle?
Based on momondo bookings for flights between London, Ontario and Seattle, the leading airline is WestJet, making up 54% of the total bookings. Other popular airlines include United Airlines with 31% and Air Canada with 15%.

Best airlines flying from London, Ontario to Seattle

Compare and see reviews for airlines that fly from London, Ontario to Seattle with momondo

Airline	Rating	Free Cancellation	Price
WestJet	PriceFrom C$ 240	Free Cancellation	Rating 7.2 3,204 reviews	Search WestJet flights
United Airlines	PriceFrom C$ 277	Free Cancellation	Rating 7.4 9,092 reviews	Search United Airlines flights
Air Canada	PriceFrom C$ 368	Free Cancellation	Rating 7.1 10,534 reviews	Search Air Canada flights

Leavenworth

Lynnwood

Marysville

Tacoma

SeaTac

Kirkland

Tukwila

Olympia

Ocean Shores

Redmond

Bainbridge Island

Ellensburg

Gig Harbor

Renton

Mukilteo

Cle Elum

Centralia

Puyallup

Federal Way

Kent

Why use momondo?

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

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from London to Seattle . Millions of users trust and use momondo every year so you are in good hands.

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

Flights from London to Seattle with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

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

Once you have performed a search for London to Seattle 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 London to Seattle right now. Can momondo alert me if prices change?

Of course. momondo tracks the price of London to Seattle flights. All you need is a valid email address and we will do the rest; it is that quick and easy.