What are the cheapest airlines flying from Seattle to London, Ontario round-trip?

Cheapflights users have booked flights from Seattle to London, Ontario round-trip from $244. Another airline that can offer you cheap pricing is United Airlines.

What is the cheapest day to fly from Seattle to London, Ontario?

Travelers seeking maximum savings on their Seattle to London, Ontario flight should consider departing on Thursday mornings when fares are most often at their lowest. Tuesday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

In terms of precipitation, rainfall in London, Ontario ranges from 2.8 - 3.9 inches per month. January is typically the wettest month, when rainfall can reach 3.9 in. March is typically the driest time to visit London, Ontario when rainfall is around 2.8 in.

If weather is an important factor for your trip to London, Ontario, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 68.0 F. Travelers looking to avoid the cold should look outside of February, when temperatures are typically at their lowest (around 21.2 F).

What is the cheapest day to fly round-trip from Seattle to London, Ontario?

Monday flights are found to be more expensive to fly from Seattle to London, Ontario. This shouldn’t discourage you from searching, as you can still find great deals by being flexible with your options. Use our search form to find deals on tickets to London, Ontario.

What is the cheapest time of day to fly from SEA to YXU?

It’s optimal to fly from Seattle to London, Ontario at noon. By choosing this option you can save up to 23% on the cost of your flight, compared to a flight in the morning.

Can I find deals for flights from Seattle to London that include hotel bookings?

Yes. In addition to deals on Seattle to London flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Seattle to London?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to London.

Can I find deals for business class flights from Seattle to London?

Yes. Cheapflights offers flight deals from Seattle to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$270+ Flights from Seattle to London, ON

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Cheap flight deals from Seattle to London

Round-trip from	$314 (Kiwi.com)
One-way from	$270 (Air Canada)

From Seattle/Tacoma Intl to London

Search Deals

One-way flight from Seattle/Tacoma Intl to London

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Find flight deals from Seattle to London

Cheapest flights from Seattle to London
Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on agosto 14, 2025.

sáb. 9/271:50 pmSEA - YXU

1 stop12h 22mWestJet

sáb. 10/48:00 pmYXU - SEA

2 stops19h 33mWestJet

Deal found 8/13

$314

sáb. 9/277:15 amSEA - YXU

2 stops11h 14mAir Canada

sáb. 10/49:55 amYXU - SEA

2 stops11h 41mAir Canada

Deal found 8/13

$503

sáb. 9/274:47 pmSEA - YXU

2 stops19h 30mUnited Airlines

sáb. 10/46:15 amYXU - SEA

3 stops20h 00mUnited Airlines

Deal found 8/13

$2,544

Best flights from Seattle to London
Discover carefully curated flight deals from Seattle to London that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated agosto 14, 2025.

sáb. 9/271:50 pmSEA - YXU

1 stop12h 22mWestJet

sáb. 10/48:00 pmYXU - SEA

2 stops19h 33mWestJet

Deal found 8/13

$314

sáb. 9/277:15 amSEA - YXU

2 stops11h 14mAir Canada

sáb. 10/49:55 amYXU - SEA

2 stops11h 41mAir Canada

Deal found 8/13

$503

sáb. 9/274:47 pmSEA - YXU

2 stops19h 30mUnited Airlines

sáb. 10/46:15 amYXU - SEA

3 stops20h 00mUnited Airlines

Deal found 8/13

$2,544

Last-minute flights from Seattle to London
Discover last-minute flight deals from Seattle to London. Data last updated agosto 14, 2025 and is based on user searches.

sáb. 9/271:50 pmSEA - YXU

1 stop12h 22mWestJet

sáb. 10/48:00 pmYXU - SEA

2 stops19h 33mWestJet

Deal found 8/13

$314

sáb. 9/277:15 amSEA - YXU

2 stops11h 14mAir Canada

sáb. 10/49:55 amYXU - SEA

2 stops11h 41mAir Canada

Deal found 8/13

$503

sáb. 9/274:47 pmSEA - YXU

2 stops19h 30mUnited Airlines

sáb. 10/46:15 amYXU - SEA

3 stops20h 00mUnited Airlines

Deal found 8/13

$2,544

One-way flights from Seattle to London
Search for one-way flight options from Seattle to London. Find affordable one-way fares based on user searches. Data last updated agosto 14, 2025.

mié. 12/318:00 pmSEA - YXU

2 stops9h 46mAir Canada

Deal found 8/13

$270

mié. 12/313:10 pmSEA - YXU

1 stop12h 34mWestJet

Deal found 8/13

$281

lun. 12/293:10 pmSEA - YXU

1 stop12h 34mWestJet

Deal found 8/13

$297

jue. 1/18:15 amSEA - YXU

1 stop10h 06mAir Canada

Deal found 8/13

$301

dom. 12/285:50 amSEA - YXU

2 stops12h 31mAir Canada

Deal found 8/13

$310

mié. 12/311:35 pmSEA - YXU

3 stops24h 31mUnited Airlines

Deal found 8/13

$325

vie. 1/26:00 amSEA - YXU

2 stops12h 21mUnited Airlines

Deal found 8/13

$364

sáb. 1/32:39 pmSEA - YXU

3 stops37h 05mMultiple Airlines

Deal found 8/13

$429

jue. 1/11:35 pmSEA - YXU

3 stops24h 31mUnited Airlines

Deal found 8/13

$483

dom. 12/286:35 amSEA - YXU

3 stops21h 09mMultiple Airlines

Deal found 8/13

$511

lun. 12/2911:27 amSEA - YXU

3 stops16h 17mMultiple Airlines

Deal found 8/13

$568

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

sáb. 9/27

1:50 pm-5:12 am

1 stop12h 22m

London

sáb. 10/4

8:00 pm-12:33 pm

2 stops19h 33m

$314

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

sáb. 9/27

7:15 am-9:29 pm

2 stops11h 14m

London

sáb. 10/4

9:55 am-6:36 pm

2 stops11h 41m

$503

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

sáb. 9/27

4:47 pm-3:17 pm

2 stops19h 30m

London

sáb. 10/4

6:15 am-11:15 pm

3 stops20h 00m

$2,544

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mié. 12/31

8:00 pm-8:46 am

2 stops9h 46m

$270

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

jue. 1/1

5:50 am-9:21 pm

2 stops12h 31m

$270

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mié. 12/31

3:10 pm-6:44 am

1 stop12h 34m

$281

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mar. 12/30

3:10 pm-6:44 am

1 stop12h 34m

$297

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

lun. 12/29

3:10 pm-6:44 am

1 stop12h 34m

$297

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

dom. 12/28

5:50 am-9:21 pm

2 stops12h 31m

$310

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

mar. 12/30

8:00 pm-8:46 am

2 stops9h 46m

$310

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/13

Showing 1-10 of 13 results

Best time to book a flight from Seattle to London

Have a flexible travel schedule? Discover the best time to fly to London from Seattle with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Reviews of airlines servicing London

Get a feel of what it's like to fly with United Airlines and Air Canada from Seattle to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.

United Airlines

7.4

Good

8,916 reviews

Reviews

1 / 20

4.0

Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??

United Airlines

7.4

Good

8,916 reviews

United Airlines

7.4

Good

8,916 reviews

Reviews

1 / 20

4.0

Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??

Air Canada

7.1

Good

9,949 reviews

United Airlines

7.4

Good

8,916 reviews

Reviews

1 / 20

4.0

Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??

Related info for your journey

What are the cheapest airlines flying from Seattle to London, Ontario round-trip?
Cheapflights users have booked flights from Seattle to London, Ontario round-trip from $244. Another airline that can offer you cheap pricing is United Airlines.
Can I find deals for flights from Seattle to London that include hotel bookings?
Yes. In addition to deals on Seattle to London flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Seattle to London?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to London.
Can I find deals for business class flights from Seattle to London?
Yes. Cheapflights offers flight deals from Seattle to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

Grand Bend

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Alternative routes for Seattle to London

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Kitchener car rentals

Top 2 airlines flying from Seattle to London

Airline	Cheapest	Average	Flexibility	On-time
Air Canada	Cheapest$244	Average$671	FlexibilityNo cancel fee	On-time67%
United Airlines	Cheapest$385	Average$660	FlexibilityNo cancel fee	On-time69%

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$270+ Cheap flights from Seattle (SEA) to London, ON (YXU)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/31. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Seattle to London with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Seattle to London

Round-trip from

One-way from

Find flight deals from Seattle to London

Cheapest flights from Seattle to LondonExplore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on agosto 14, 2025.

Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on agosto 14, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Seattle to London that are best for you.

Best time to book a flight from Seattle to London

Have a flexible travel schedule? Discover the best time to fly to London from Seattle with our price prediction graph.

Reviews of airlines servicing London

Get a feel of what it's like to fly with United Airlines and Air Canada from Seattle to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Seattle to London. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What are the cheapest airlines flying from Seattle to London, Ontario round-trip?

Can I find deals for flights from Seattle to London that include hotel bookings?

How can I find direct flights from Seattle to London?

Can I find deals for business class flights from Seattle to London?

Traveling to a place near London?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Seattle to London

See prices for flight routes from nearby airports that may be better suited for you.

Top 2 airlines flying from Seattle to London

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Travel Smart

Cheapest flights from Seattle to London
Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on agosto 14, 2025.