London

$243+ 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 9/20. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
Aug 26 — Sep 21
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or January, booked 50 days in advance, depart on a Tuesday or Wednesday 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 August 21, 2025.

Round-trip from

$504
(Mytrip)

One-way from

$243
(Kiwi.com)

Popular in

June

Cheapest in

October

Average price

$685

Good round-trip deal

$597 or less

Good one-way deal

$452 or less
From Seattle/Tacoma Intl to London (LON)
One-way flight from Seattle/Tacoma Intl to London (LON)
Highest demand for flights based on searches. 15% potential increase in price ($137 potential increase over avg. RT price).
Cheapest flight prices on average. 2% potential price decrease ($23 potential savings vs. average RT price).
Average for round-trip flights in August 2025
Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).

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 August 21, 2025.

This Mytrip deal was found by Cheapflights users on 8/21. 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.
Sun 9/711:30 pmSEA - LGW
1 stop31h 05mIcelandair
Tue 9/233:40 pmLGW - SEA
1 stop13h 00mIcelandair
Deal found 8/21$504
This Gotogate deal was found by Cheapflights users on 8/19. 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.
Sun 9/73:45 pmSEA - LHR
1 stop20h 35mIcelandair
Tue 9/239:25 pmLHR - SEA
1 stop31h 15mIcelandair
Deal found 8/19$504
This oojo deal was found by Cheapflights users on 8/20. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/57:00 pmSEA - LGW
1 stop11h 40mIcelandair
Tue 9/233:40 pmLGW - SEA
1 stop13h 00mIcelandair
Deal found 8/20$505
This Gotogate deal was found by Cheapflights users on 8/19. 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.
Tue 10/75:35 pmSEA - LHR
Nonstop9h 45mMultiple Airlines
Wed 10/226:15 amLHR - SEA
1 stop13h 00mMultiple Airlines
Deal found 8/19$505
This Gotogate deal was found by Cheapflights users on 8/19. 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.
Sun 9/75:35 pmSEA - LHR
Nonstop9h 45mVirgin Atlantic
Tue 9/231:25 pmLHR - SEA
Nonstop10h 05mVirgin Atlantic
Deal found 8/19$506
This oojo deal was found by Cheapflights users on 8/21. 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 oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/207:00 pmSEA - LHR
1 stop32h 55mIcelandair
Sat 10/119:25 pmLHR - SEA
1 stop31h 15mIcelandair
Deal found 8/21$507
This Mytrip deal was found by Cheapflights users on 8/20. 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 9/37:00 pmSEA - LHR
1 stop32h 55mIcelandair
Sat 9/139:25 pmLHR - SEA
1 stop22h 00mIcelandair
Deal found 8/20$508
This FlightHub deal was found by Cheapflights users on 8/21. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/87:00 pmSEA - LGW
1 stop11h 35mIcelandair
Thu 9/183:40 pmLGW - SEA
1 stop13h 00mIcelandair
Deal found 8/21$509
This Delta deal was found by Cheapflights users on 8/21. 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.
Tue 9/98:25 pmSEA - LHR
Nonstop9h 50mDelta
Thu 9/186:15 amLHR - SEA
1 stop13h 00mDelta
Deal found 8/21$509
This FlightHub deal was found by Cheapflights users on 8/19. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/137:00 pmSEA - LGW
1 stop11h 35mIcelandair
Mon 9/223:40 pmLGW - SEA
1 stop13h 00mIcelandair
Deal found 8/19$510
This Delta deal was found by Cheapflights users on 8/19. 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.
Wed 10/157:50 amSEA - LHR
1 stop14h 55mDelta
Tue 10/286:20 amLHR - SEA
1 stop13h 05mDelta
Deal found 8/19$510
This Gurufare deal was found by Cheapflights users on 8/20. 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 Gurufare is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/237:00 pmSEA - LGW
1 stop11h 40mIcelandair
Wed 11/1211:55 amLGW - SEA
1 stop13h 05mIcelandair
Deal found 8/20$511

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 August 21, 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

Sun 9/7

11:30 pm-2:35 pm

1 stop31h 05m

London Gatwick

Tue 9/23

3:40 pm-8:40 pm

1 stop13h 00m

$504

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Fri 9/5

7:00 pm-2:40 pm

1 stop11h 40m

London Gatwick

Tue 9/23

3:40 pm-8:40 pm

1 stop13h 00m

$505

SeattleLondon

SEA - STN

SEASTN

Seattle/Tacoma Intl

Wed 10/29

9:05 pm-7:35 pm

1 stop15h 30m

London Stansted

Wed 11/5

8:30 am-6:20 pm

1 stop17h 50m

$507

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 9/10

11:30 pm-2:40 pm

1 stop31h 10m

London Gatwick

Thu 9/25

3:40 pm-8:40 pm

1 stop13h 00m

$507

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 10/7

8:25 pm-2:15 pm

Nonstop9h 50m

London Heathrow

Wed 10/15

11:30 am-5:40 pm

1 stop14h 10m

$509

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 9/14

5:35 pm-11:20 am

Nonstop9h 45m

London Heathrow

Wed 9/24

6:15 am-5:40 pm

1 stop19h 25m

$509

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 10/22

5:35 pm-11:20 am

Nonstop9h 45m

London Heathrow

Wed 10/29

6:20 am-2:20 pm

1 stop15h 00m

$509

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 9/9

7:00 pm-2:40 pm

1 stop11h 40m

London Gatwick

Thu 9/18

3:40 pm-8:40 pm

1 stop13h 00m

$509

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 9/14

5:35 pm-11:20 am

Nonstop9h 45m

London Heathrow

Thu 9/25

6:15 am-5:40 pm

1 stop19h 25m

$509

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 9/9

7:00 pm-2:40 pm

1 stop11h 40m

London Gatwick

Tue 9/16

3:40 pm-8:40 pm

1 stop13h 00m

$509

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/20

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 August 8, 2025.

Booking 50 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 $1,097). 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 August 21, 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 14% 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 August 21, 2025.

The most flights from SEA to LON are scheduled on a Wednesday (25 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (15 on average).

What’s the top layover airport for flights from Seattle to London?

Share of 1-stop round-trip flights from Seattle to London chosen by Cheapflights users in the past 12 months, using the same layover each way.

Reykjavik (KEF) – chosen by Cheapflights users on 83% of 1-stop itineraries from Seattle to London on Cheapflights.

What’s the cheapest layover airport for flights from Seattle to London?

Average round-trip fare for 1-stop flights from Seattle to London, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Reykjavik (KEF) is the most affordable 1-stop option, with an average round-trip price of $575.

What’s the fastest layover option from Seattle to London?

Shortest average travel time for 1-stop one-way flights from Seattle to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 11h 35m.

Which airport typically offers the quickest layover for flights from Seattle to London?

Average layover duration for 1-stop one-way flights from Seattle to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Dublin (DUB) offer the fastest connection on this route, with an average layover time of 2h 03m.

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 August 21, 2025.
Peruse reviews from past customers who have flown with Delta, Virgin Atlantic, and Icelandair from Seattle to London to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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!
8.0
Very good
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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!
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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!
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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!
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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!
8.0
Very good

Overall

8.0

Crew

8.5

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

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 20 flights from Seattle/Tacoma Intl to London per day from 15 different airlines.

  • How long is the flight from Seattle to London?

    A quick flight from Seattle to London can take about 9h 50m. Icelandair provides one of the quickest options available for as low as $509. The distance between Seattle and London is about 4783 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

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

    Cheapflights users have booked flights from Seattle to London round-trip from $378. Other airlines that can offer you cheap pricing are Icelandair, from $497, and Scandinavian Airlines, from $532. Users have found that Lufthansa is 50% cheaper than the other options available to this destination.

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

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

    Consider Aeromexico (88%), 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 $372. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for $477 on average our data indicates $2,130 when flying from Seattle to London.

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

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

    Reykjavik travelers tend to visit Harpa, Hallgrímskirkja, and Laugardalslaug Geothermal Pool more than anywhere else. Harpa, Hallgrímskirkja, and Laugardalslaug Geothermal Pool are located about 23.3 mi, 23.2 mi, and 24.6 mi, respectively from Reykjavik Keflavik Intl. Travelers in need of a car in Reykjavik can rent one for about $63 per day.

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

  • 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 $1,097). 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 London?

Book flights to London if you plan to visit one of these locations
Hounslow
Hayes
Thornton Heath
Southend-on-Sea
Harrow
Canterbury
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Dartford
Dover
Orpington
Gatwick
Borehamwood
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Folkestone
Chichester
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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 August 21, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$378Average$865FlexibilityNo cancel feeOn-time76%
IcelandairCheapest$497Average$656FlexibilityNo cancel feeOn-time76%
Scandinavian AirlinesCheapest$532Average$871FlexibilityNo cancel feeOn-time77%
Air FranceCheapest$532Average$845FlexibilityNo cancel feeOn-time77%
United AirlinesCheapest$547Average$870FlexibilityNo cancel feeOn-time69%
FinnairCheapest$556Average$729FlexibilityNo cancel feeOn-time76%
British AirwaysCheapest$564Average$816FlexibilityNo cancel feeOn-time70%
DeltaCheapest$574Average$849FlexibilityNo cancel feeOn-timeN/A
Aer LingusCheapest$576Average$816FlexibilityNo cancel feeOn-timeN/A
IberiaCheapest$578Average$732FlexibilityNo cancel feeOn-time77%

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