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Cheap flights from Seattle to London, ON from C$ 294

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 17/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YXU
9 Apr — 16 Apr1
1 adult

Cheap flight deals from Seattle to London

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to London (YXU). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 4 April 2025.

Round-trip from

C$ 294
WestJet
  • WestJet
  • 17/5-24/5
  • 2 total stops
  • 19h 02m total
  • Seattle 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 4 April 2025.

Sat 17/57:05 a.m.SEA - YXU
1 stop9h 04mWestJet
Sat 24/56:00 a.m.YXU - SEA
1 stop9h 58mWestJet
Deal found 4/4C$ 294
Sat 17/57:20 a.m.SEA - YXU
2 stops11h 08mAir Canada
Sat 24/59:55 a.m.YXU - SEA
2 stops12h 42mAir Canada
Deal found 4/4C$ 380
Sat 31/510:15 p.m.SEA - YXU
2 stops13h 43mUnited Airlines
Sat 7/63:35 p.m.YXU - SEA
2 stops12h 24mUnited Airlines
Deal found 4/4C$ 401
Sat 17/56:00 a.m.SEA - YXU
3 stops20h 14mMultiple Airlines
Sat 24/58:00 p.m.YXU - SEA
2 stops19h 31mMultiple Airlines
Deal found 4/4C$ 547

Cheapflights Fare Finder

Customize your flight search to find flights from Seattle to London that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 4 April 2025.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Seattle

Fly to

London

Route

Depart

Return

Price

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 17/5

7:05 a.m.-7:09 p.m.

1 stop9h 04m

London

Sat 24/5

6:00 a.m.-12:58 p.m.

1 stop9h 58m

C$ 294

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 17/5

7:20 a.m.-9:28 p.m.

2 stops11h 08m

London

Sat 24/5

9:55 a.m.-7:37 p.m.

2 stops12h 42m

C$ 380

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 31/5

10:15 p.m.-2:58 p.m.

2 stops13h 43m

London

Sat 7/6

3:35 p.m.-12:59 a.m.

2 stops12h 24m

C$ 401

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Sat 17/5

6:00 a.m.-5:14 a.m.

3 stops20h 14m

London

Sat 24/5

8:00 p.m.-12:31 p.m.

2 stops19h 31m

C$ 547

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Thu 31/7

7:35 p.m.-5:14 a.m.

1 stop6h 39m

C$ 776

SeattleLondon

SEA - YXU

SEAYXU

Seattle/Tacoma Intl

Wed 30/7

12:20 a.m.-5:07 p.m.

2 stops13h 47m

C$ 1,310

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/4

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

What is the cheapest month to book a flight from Seattle to London, Ontario?

Currently, October is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of C$ 243). Flying from Seattle to London, Ontario in December is currently the most expensive (average of C$ 478). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Rainfall in London by month

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

In terms of precipitation, rainfall in London, Ontario ranges from 70.0 - 100.0 mm per month. January is typically the wettest month, when rainfall can reach 100.0 mm. March is typically the driest time to visit London, Ontario when rainfall is around 70.0 mm.

Temperature in London by month

Plan your trip to London by taking into account the average temperature totals 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 20.0 C. Travellers hoping to avoid the cold should look outside of February, when temperatures are typically at their lowest (around -6.0 C).

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated 4 April 2025.
United Airlines
7.4
Good
8,618 reviews
Check prices

Entertainment

7.0

Boarding

7.7

Food

6.6

Overall

7.4

Comfort

7.3

Crew

8.1

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
8,618 reviews
United Airlines
7.4
Good
8,618 reviews
Check prices

Entertainment

7.0

Boarding

7.7

Food

6.6

Overall

7.4

Comfort

7.3

Crew

8.1

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
2,795 reviews
United Airlines
7.4
Good
8,618 reviews
Check prices

Entertainment

7.0

Boarding

7.7

Food

6.6

Overall

7.4

Comfort

7.3

Crew

8.1

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
7.0
Good
9,040 reviews
United Airlines
7.4
Good
8,618 reviews
Check prices

Entertainment

7.0

Boarding

7.7

Food

6.6

Overall

7.4

Comfort

7.3

Crew

8.1

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

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?

    WestJet, at C$ 294, was found to be the cheapest airline from Seattle to London, Ontario.Alternate airlines to your destination round-trip include Air Canada and 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.

  • What is the cheapest month to book a flight from Seattle to London, Ontario?

    Currently, October is the cheapest month in which you can book a flight from Seattle to London, Ontario (average of C$ 243). Flying from Seattle to London, Ontario in December is currently the most expensive (average of C$ 478). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Grand Bend
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Need flexible booking options for your flight to London from Seattle? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

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