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$253+ Cheap flights from Seattle (SEA) to London (LON)

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 8/1. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in January or October, booked 81 days in advance, depart on a Tuesday or Monday and return on a Wednesday

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 (LON). 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 June 12, 2025.

Round-trip from

$665
(Gotogate)

One-way from

$253
(Trip.com)

Popular in

June

Cheapest in

January

Average price

$1,028

Good round-trip deal

$665 or less

Good one-way deal

$445 or less
From Seattle/Tacoma Intl to London (LON)
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One-way flight from Seattle/Tacoma Intl to London (LON)
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Highest demand for flights based on searches. 15% potential increase in price ($147 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($23 potential savings vs. average RT price).
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Average for round-trip flights in June 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
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Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).
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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 June 12, 2025.

This Gotogate deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/411:30 pmSEA - LGW
1 stop31h 10mIcelandair
Fri 9/193:40 pmLGW - SEA
1 stop13h 00mIcelandair
Deal found 6/10$665
This Delta deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/65:10 pmSEA - LHR
1 stop14h 30mDelta
Tue 10/215:25 pmLHR - SEA
Nonstop10h 25mDelta
Deal found 6/11$665
This Icelandair deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Icelandair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/243:45 pmSEA - LHR
1 stop12h 10mIcelandair
Mon 9/159:25 pmLHR - SEA
1 stop28h 25mIcelandair
Deal found 6/10$666
This SWISS deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure SWISS is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2010:55 amSEA - LGW
2 stops23h 00mSWISS
Tue 9/236:35 pmLGW - SEA
2 stops32h 01mSWISS
Deal found 6/10$667
This SWISS deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure SWISS is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2710:00 amSEA - LHR
2 stops22h 25mSWISS
Thu 9/115:10 pmLHR - SEA
2 stops33h 26mSWISS
Deal found 6/10$667
This Ovago deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Ovago is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/277:49 amSEA - LGW
2 stops18h 51mBritish Airways
Thu 8/2810:40 amLGW - SEA
2 stops21h 00mBritish Airways
Deal found 6/10$668
This United Airlines deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/187:34 pmSEA - LHR
2 stops17h 06mUnited Airlines
Thu 8/287:30 amLHR - SEA
2 stops18h 27mUnited Airlines
Deal found 6/11$668
This Finnair deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Finnair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/271:30 pmSEA - LHR
Nonstop9h 20mFinnair
Mon 8/119:30 amLHR - SEA
1 stop14h 30mFinnair
Deal found 6/10$669
This SWISS deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure SWISS is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/162:29 pmSEA - LCY
2 stops19h 01mSWISS
Tue 10/77:20 pmLCY - SEA
2 stops31h 16mSWISS
Deal found 6/11$670
This Mytrip deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/133:45 pmSEA - STN
2 stops22h 45mMultiple Airlines
Wed 8/209:05 amSTN - SEA
2 stops16h 45mMultiple Airlines
Deal found 6/9$672
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/197:00 pmSEA - LGW
1 stop11h 40mMultiple Airlines
Thu 9/2510:00 amLGW - SEA
1 stop20h 05mMultiple Airlines
Deal found 6/10$674
This Air France deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/118:25 pmSEA - LHR
Nonstop9h 50mAir France
Thu 7/245:25 pmLHR - SEA
Nonstop10h 20mAir France
Deal found 6/9$675

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 2,558,603 searches. Data last updated June 12, 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 - LGW

SEALGW

Seattle/Tacoma Intl

Thu 9/4

11:30 pm-2:40 pm

1 stop31h 10m

London Gatwick

Fri 9/19

3:40 pm-8:40 pm

1 stop13h 00m

$665

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 10/6

5:10 pm-3:40 pm

1 stop14h 30m

London Heathrow

Tue 10/21

5:25 pm-7:50 pm

Nonstop10h 25m

$665

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 8/20

10:55 am-5:55 pm

2 stops23h 00m

London Gatwick

Tue 9/23

6:35 pm-6:36 pm

2 stops32h 01m

$667

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 8/27

10:00 am-4:25 pm

2 stops22h 25m

London Heathrow

Wed 9/10

5:10 pm-6:36 pm

2 stops33h 26m

$667

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Sun 7/27

7:49 am-10:40 am

2 stops18h 51m

London Gatwick

Thu 8/28

10:40 am-11:40 pm

2 stops21h 00m

$668

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 8/18

7:34 pm-8:40 pm

2 stops17h 06m

London Heathrow

Thu 8/28

7:30 am-5:57 pm

2 stops18h 27m

$668

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 7/27

8:20 pm-1:40 pm

Nonstop9h 20m

London Heathrow

Mon 8/11

7:30 am-4:00 pm

1 stop16h 30m

$669

SeattleLondon

SEA - LCY

SEALCY

Seattle/Tacoma Intl

Tue 9/16

2:29 pm-5:30 pm

2 stops19h 01m

London City

Tue 10/7

7:20 pm-6:36 pm

2 stops31h 16m

$670

SeattleLondon

SEA - STN

SEASTN

Seattle/Tacoma Intl

Wed 8/13

3:45 pm-10:30 pm

2 stops22h 45m

London Stansted

Wed 8/20

9:05 am-5:50 pm

2 stops16h 45m

$672

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Fri 9/19

7:00 pm-2:40 pm

1 stop11h 40m

London Gatwick

Thu 9/25

10:00 am-10:05 pm

1 stop20h 05m

$674

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 60 results
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The best insider tips for Seattle to London flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to London trip
Airports
SEA

Plan to arrive at SEA at least two hours before your flight due to potentially long security lines.

Read more about SEAby Brandon Schultz
LHR

Take the Heathrow Express for the fastest route into central London from LHR, arriving at Paddington Station.

Read more about LHRby Ramsey Qubein
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on LHR

Ramsey Qubein

Ramsey Qubein

An avid traveler and aviation expert who has visited 173 countries, all 50 states and seven continents, Ramsey Qubein flies nearly 400,000 miles a year. As a North Carolina-based freelance journalist for publications including Conde Nast Traveler, Forbes, USA Today and Bloomberg among others, he explores the latest trends in aviation, hospitality, cruises and business.

Read more
Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz

Brandon Schultz

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more

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

How far ahead should I book a flight from Seattle to London?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to London. Price data was last updated on June 9, 2025.

Booking 81 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to London. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, November is the cheapest month in which you can book a flight from Seattle to London (average of $661). Flying from Seattle to London in June is currently the most expensive (average of $1,108). 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 SEA to LON?

Find hourly flight availability from Seattle to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 12, 2025.

One of the essential ways to save on airfare from Seattle to London is to remain as flexible as possible. Flights that are in the morning tend to be the most expensive. A flight in the evening could potentially save you up to 12% on airfare.

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

Use this chart to determine the cheapest time to fly round-trip from Seattle to London. Price data was last updated on December 16, 2024.

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

Weekly flight availability from Seattle to London

Explore weekly flight availability from Seattle to London. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 12, 2025.

The most flights from SEA to LON are scheduled on a Monday (22 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (16 on average).

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 ranges from 1.6 - 2.8 inches per month. January is typically the wettest month, when rainfall can reach 2.8 in. July is typically the driest time to visit London when rainfall is around 1.6 in.

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, 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 62.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 39.2 F).

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 June 12, 2025.
See what other customers who have flown with Delta, KLM and Finnair from Seattle to London have to say. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Delta
8.0
Very good
7,950 reviews
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
KLM
7.8
Good
1,358 reviews
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Finnair
7.6
Good
1,290 reviews
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Air France
7.5
Good
1,463 reviews
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
SWISS
7.5
Good
1,623 reviews
Delta
8.0
Very good
7,950 reviews

Entertainment

7.9

Boarding

8.2

Comfort

7.9

Food

7.3

Overall

8.0

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

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 airport do you fly from for flights from Seattle to London?

    If you book a flight to London from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There are 21 flights from Seattle/Tacoma Intl to London per day from 15 different airlines.

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

    Cheapflights users have booked flights from Seattle to London round-trip from $665. Other airlines that can offer you cheap pricing are Delta, from $665, and Scandinavian Airlines, from $666. Users have found that Icelandair is 14% cheaper than the other options available to this destination.

  • What are the cheapest airlines to fly from Seattle to London one-way?

    One-way options have recently been found by users for as low as $254 on Icelandair. Other airlines that offer cheap prices include JetBlue from $369 and Air Canada from $387 one-way.

  • What are the most popular routes from Seattle to London?

    When deciding which route to take from Seattle to London consider Seattle/Tacoma Intl - London Heathrow, Seattle/Tacoma Intl - London Gatwick or Seattle/Tacoma Intl - London City as they are the most popular.

  • What are the most reliable airlines from Seattle to London?

    Consider Aeromexico (92%), KLM (87%) or Air France (87%) when booking your flight. These represent the most reliable airlines when flying from Seattle to London.

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for $380. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for $464 on average our data indicates $2,939 when flying from Seattle to London.

  • Where are the most common layover locations when flying from Seattle to London?

    The most popular layover on flights from Seattle to London is Reykjavik.

  • What are some popular things to do or see while on a layover in Reykjavik?

    Reykjavik travelers tend to visit Hallgrímskirkja, Harpa, and Laugardalslaug Geothermal Pool more than anywhere else. Hallgrímskirkja, Harpa, and Laugardalslaug Geothermal Pool are located about 23.2 mi, 23.3 mi, and 24.6 mi, respectively from Reykjavik Keflavik Intl. Travelers in need of a car in Reykjavik can rent one for about $66 per day.

  • Where are the least popular layover locations for Seattle to London flights?

    Flights departing from Seattle and landing in London layover in Dublin least frequently.

  • 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?

    Currently, November is the cheapest month in which you can book a flight from Seattle to London (average of $661). Flying from Seattle to London in June is currently the most expensive (average of $1,108). 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

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Hayes
Hounslow
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Luton
Canterbury
Harrow
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Orpington
Watford
Croydon
Folkestone
Borehamwood
Sutton
Aylesbury
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Brentwood
Chichester
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Arundel

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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.
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Top 10 airlines flying from Seattle to London

Discover the top 10 airlines that operate flights from Seattle to London. 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 2,558,603 searches. Data last updated June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$378Average$819FlexibilityNo cancel feeOn-time76%
IcelandairCheapest$503Average$660FlexibilityNo cancel feeOn-time76%
Scandinavian AirlinesCheapest$532Average$871FlexibilityNo cancel feeOn-time77%
United AirlinesCheapest$550Average$881FlexibilityNo cancel feeOn-time69%
IberiaCheapest$579Average$734FlexibilityNo cancel feeOn-time77%
Aer LingusCheapest$583Average$794FlexibilityNo cancel feeOn-timeN/A
FinnairCheapest$597Average$728FlexibilityNo cancel feeOn-time76%
Air FranceCheapest$597Average$876FlexibilityNo cancel feeOn-time77%
KLMCheapest$597Average$833FlexibilityNo cancel feeOn-time75%
British AirwaysCheapest$611Average$856FlexibilityNo cancel feeOn-time70%

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