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Cheap flights from London, ON to Seattle from C$ 403

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 15/8. Fares are subject to change and may not be available on all flights or dates of travel.
YXU — SEA
30 Mar — 6 Apr1
1 adult

Cheap flight deals from London to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from London (YXU) to Seattle (SEA). 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 25 March 2025.

Round-trip from

C$ 403

Popular in

April

Cheapest in

September

Average price

C$ 885
WestJet
  • WestJet
  • 15/8-22/8
  • 2 total stops
  • 24h 42m total
  • London to Seattle
Search Deals
Highest demand for flights based on searches. 33% potential increase in price (C$ 496 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 17% potential price decrease (C$ 143 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2025
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Find flight deals from London to Seattle

Cheapest flights from London to Seattle
Explore the most affordable flight options available from London to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 25 March 2025.

Fri 15/86:00 a.m.YXU - SEA
1 stop15h 38mWestJet
Fri 22/87:05 a.m.SEA - YXU
1 stop9h 04mWestJet
Deal found 24/3C$ 403
Thu 10/49:55 a.m.YXU - SEA
3 stops28h 54mUnited Airlines
Thu 17/43:24 p.m.SEA - YXU
2 stops14h 49mUnited Airlines
Deal found 24/3C$ 1,156

Cheapflights Fare Finder

Customize your flight search to find flights from London to Seattle 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 25 March 2025.
Use the filters below to find and compare flights from London to Seattle that are best for you.

Fly from

London

Fly to

Seattle

Route

Depart

Return

Price

LondonSeattle

YXU - SEA

YXUSEA

London

Fri 15/8

6:00 a.m.-6:38 p.m.

1 stop15h 38m

Seattle/Tacoma Intl

Fri 22/8

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

1 stop9h 04m

C$ 403

LondonSeattle

YXU - SEA

YXUSEA

London

Thu 10/4

9:55 a.m.-11:49 a.m.

3 stops28h 54m

Seattle/Tacoma Intl

Thu 17/4

3:24 p.m.-9:13 a.m.

2 stops14h 49m

C$ 1,156

LondonSeattle

YXU - SEA

YXUSEA

London

Sun 30/3

8:00 p.m.-8:38 p.m.

2 stops27h 38m

C$ 662

LondonSeattle

YXU - SEA

YXUSEA

London

Sun 30/3

3:20 p.m.-9:41 p.m.

1 stop9h 21m

C$ 824

Flights are sorted by cheapest round-trip flights first.

Deals found on 24/3

Best time to book a flight from London to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from London 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 London to Seattle

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

Currently, January is the cheapest month in which you can book a flight from London, Ontario to Seattle (average of C$ 261). Flying from London, Ontario to Seattle in December is currently the most expensive (average of C$ 353). 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.

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

Find hourly flight availability from London to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 25 March 2025.

One of the essential ways to save on airfare from London, Ontario to Seattle is to remain as flexible as possible. Flights that are in the morning tend to be the most expensive. A flight at noon could potentially save you up to 2% on airfare.

Rainfall in Seattle by month

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

In terms of precipitation, rainfall in Seattle ranges from 18.0 - 168.0 mm per month. November is typically the wettest month, when rainfall can reach 168.0 mm. July is typically the driest time to visit Seattle when rainfall is around 18.0 mm.

Temperature in Seattle by month

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

If weather is an important factor for your trip to Seattle, 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 19.0 C. Travellers hoping to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 5.0 C).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated 25 March 2025.
United Airlines
7.4
Good
8,605 reviews
Check prices

Boarding

7.7

Comfort

7.3

Entertainment

7.0

Overall

7.4

Food

6.6

Crew

8.1

Reviews

1 / 20
4.0
Okay

Patti,Feb 2025

FCO - EWR

The food was inedible! We are in the food business and aren’t sure who got this contract. But prisoners eat better. The food was so bad. I ate just a small amount and it made me nauseous. Everything is over microwaved too. And what is with the options? Vegan and vegetarian, but no keto or carnivore? I get that may be more expensive. But I’d gladly pay if it even was an option. But it’s not. There are many fresh options that could have been offered that don’t have to be heated too!
United Airlines
7.4
Good
8,605 reviews
United Airlines
7.4
Good
8,605 reviews
Check prices

Boarding

7.7

Comfort

7.3

Entertainment

7.0

Overall

7.4

Food

6.6

Crew

8.1

Reviews

1 / 20
4.0
Okay

Patti,Feb 2025

FCO - EWR

The food was inedible! We are in the food business and aren’t sure who got this contract. But prisoners eat better. The food was so bad. I ate just a small amount and it made me nauseous. Everything is over microwaved too. And what is with the options? Vegan and vegetarian, but no keto or carnivore? I get that may be more expensive. But I’d gladly pay if it even was an option. But it’s not. There are many fresh options that could have been offered that don’t have to be heated too!
WestJet
7.2
Good
2,785 reviews
United Airlines
7.4
Good
8,605 reviews
Check prices

Boarding

7.7

Comfort

7.3

Entertainment

7.0

Overall

7.4

Food

6.6

Crew

8.1

Reviews

1 / 20
4.0
Okay

Patti,Feb 2025

FCO - EWR

The food was inedible! We are in the food business and aren’t sure who got this contract. But prisoners eat better. The food was so bad. I ate just a small amount and it made me nauseous. Everything is over microwaved too. And what is with the options? Vegan and vegetarian, but no keto or carnivore? I get that may be more expensive. But I’d gladly pay if it even was an option. But it’s not. There are many fresh options that could have been offered that don’t have to be heated too!

Related info for your journey

Find useful and relevant information for your journey from London to Seattle. 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 London, Ontario to Seattle round-trip?

    According to our current data, WestJet (C$ 403), and United Airlines (C$ 1,156) offers the cheapest pricing from London, Ontario to Seattle. WestJet is 40% cheaper than the average price of flights available within the next 90 days to this destination.

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

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

  • How can I find direct flights from London to Seattle?

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

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

    Yes. Cheapflights offers flight deals from London to Seattle 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 London, Ontario to Seattle?

    Currently, January is the cheapest month in which you can book a flight from London, Ontario to Seattle (average of C$ 261). Flying from London, Ontario to Seattle in December is currently the most expensive (average of C$ 353). 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 London?

Book flights to London if you plan to visit one of these locations
SeaTac
Tukwila
Marysville
Bothell
Leavenworth
Tacoma
Olympia
Lynnwood

Browse thousands of different options on Cheapflights for your next trip

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Top airline flying from London to Seattle

Discover the top airline that operate flights from London to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 25 March 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 374AverageC$ 470FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

Fly with Cheapflights

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How does Cheapflights help users find flights from London to Seattle?

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Why should you use Cheapflights to find cheap flight tickets from London to Seattle?

Cheapflights helps you find that perfect flight to Seattle from London by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from London to Seattle with no change fees?

Certainly. Search results for flights to Seattle from London shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from London to Seattle become cheaper?

Yes, Cheapflights offers price alerts on London to Seattle flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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