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 $464. 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.

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.

Most accurate provider : When it comes to deals on Seattle-London, Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-London, Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-London, Ontario flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Seattle-London, Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London, Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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.

$238+ Flights from Seattle to London, ON

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Find cheap flights from Seattle to London with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Seattle to London

Most accurate provider	FlightHub 3 stars
Most trusted provider	FlightHub 3 stars
Round-trip from	$449 (Kiwi.com)

Provider with most accurate pricing for Seattle/Tacoma Intl-London flight deals.

Search Deals

Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-London flights.

Search Deals

From Seattle/Tacoma Intl to London

Search Deals

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 March 21, 2025.

Sat 5/317:05 amSEA - YXU

1 stop19h 09mWestJet

Sat 6/76:00 amYXU - SEA

1 stop9h 58mWestJet

Deal found 3/21

$349

Mon 5/58:56 pmSEA - YXU

3 stops33h 22mMultiple Airlines

Mon 5/128:00 pmYXU - SEA

1 stop27h 28mMultiple Airlines

Deal found 3/21

$419

Sun 5/49:10 amSEA - YXU

2 stops21h 08mUnited Airlines

Sun 5/116:15 amYXU - SEA

2 stops18h 16mUnited Airlines

Deal found 3/20

$660

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 March 21, 2025.

Sun 5/47:05 amSEA - YXU

1 stop19h 09mMultiple Airlines

Sun 5/118:00 pmYXU - SEA

2 stops31h 10mMultiple Airlines

Deal found 3/19

$449

Sun 5/47:05 amSEA - YXU

1 stop19h 09mWestJet

Sun 5/118:00 pmYXU - SEA

1 stop19h 58mWestJet

Deal found 3/20

$464

Sun 5/49:10 amSEA - YXU

2 stops21h 08mUnited Airlines

Sun 5/116:15 amYXU - SEA

2 stops18h 16mUnited Airlines

Deal found 3/20

$660

Cheapflights Fare Finder

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

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 5/31

7:05 am-5:14 am

1 stop19h 09m

London

Sat 6/7

6:00 am-12:58 pm

1 stop9h 58m

$349

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 5/5

8:56 pm-9:18 am

3 stops33h 22m

London

Mon 5/12

8:00 pm-8:28 pm

1 stop27h 28m

$419

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sun 5/4

9:10 am-9:18 am

2 stops21h 08m

London

Sun 5/11

6:15 am-9:31 pm

2 stops18h 16m

$660

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 5/5

3:39 pm-7:09 pm

2 stops24h 30m

$238

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 4/24

3:05 pm-9:13 am

2 stops15h 08m

$325

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Mon 5/5

7:05 am-7:09 pm

1 stop9h 04m

$356

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 4/23

5:05 pm-2:48 pm

3 stops18h 43m

$507

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/21

Compare providers for flights from Seattle to London

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to London in March.

Provider	Price Accuracy	Trust Score*
FlightHub	Price Accuracy3 stars	Trust Score*3 stars
eDreams	Price Accuracy3 stars	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Seattle-London, Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-London, Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-London, Ontario flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Seattle-London, Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London, Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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.

Cheapflights Insights

Everything you need to know about your flight from Seattle to London

Rainfall in London by month

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.

Temperature in London by month

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).

Reviews of airlines servicing London

United Airlines

7.4

Good

8,605 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

8,605 reviews

United Airlines

7.4

Good

8,605 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??

WestJet

7.2

Good

2,783 reviews

United Airlines

7.4

Good

8,605 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 $464. 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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Niagara Falls car rentals

Top airline flying from Seattle to London

Airline	Cheapest	Average	Flexibility	On-time
Air Canada	Cheapest$205	Average$399	FlexibilityNo cancel fee	On-time67%

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$238+ 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 5/5. 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

Most accurate provider

Most trusted provider

Round-trip 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 March 21, 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 March 21, 2025.

Cheapflights Fare Finder

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

Compare providers for flights from Seattle to London

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to London in March.

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.

Cheapflights Insights

Everything you need to know about your flight from Seattle to London

Rainfall in London by month

Plan your trip to London by taking into account the average rainfall totals by month.

Temperature in London by month

Plan your trip to London by taking into account the average temperature totals by month.

Reviews of airlines servicing London

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 Seattle?

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Seattle to London

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

Top airline flying from Seattle to London

100% Free

Book with Flexibility

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 March 21, 2025.