What is the cheapest airline that flies from Seattle/Tacoma Intl to London Heathrow?

Icelandair, Scandinavian Airlines, and Lufthansa are the most popular carriers operating from Seattle/Tacoma Intl to London Heathrow

How often are flights from Seattle to London delayed?

Historically, on average around 17% of flights between Seattle and London have experienced a delay on any given week. The average delay length over the past 12 months has been 131 minutes.

How many flights depart from Seattle to London Heathrow Airport on average per week?

77 flights are operational weekly from Seattle to London Heathrow Airport as of November 2025. The most popular departure day for this route is Mon, with 19% of flights per week taking off on this day.

What day of the week experiences the fewest flight delays on this route?

Friday is statistically the day of the week that experiences the fewest delays on this flight route. Sunday has historically seen more delays on average compared to the rest of the week.

Which airline has the best punctuality record on Seattle to London flights?

According to our data, La Costena have had the fewest delays on this route over the last 12 months, with no flights being classified as delayed.

What is the most punctual flight time for Seattle to London flights?

Generally, flights departing in the early afternoon tend to experience fewer delays. Flights departing in the evening have, in the past, seen delays more frequently in comparison.

How many flights depart from Seattle to London Heathrow Airport on average per day?

As of November 2025, 11 flights take off from Seattle and land in London Heathrow Airport each day. The most common flight departure time for this route is 16:00, with 54% of daily flights taking off in the afternoon.

When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?

Prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport are refreshed on a daily basis.

How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?

There are 2 operators available for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport as of November 2025.

How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Heathrow Airport?

Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to London Heathrow Airport.

What documentation or ID do you need to fly to London Heathrow Airport?

The travel and health documents you'll need for your trip to London Heathrow Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London Heathrow Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

£270 Cheap Flights from Seattle to London Heathrow Airport in 2025/26

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19:00 - 20:20SEA-LHR

17h 20m1 stop

21:25 - 17:50LHR-SEA

28h 25m1 stop

£401Icelandair

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Tue, 21 Apr - Tue, 5 May

19:00 - 20:20SEA-LHR

17h 20m1 stop

21:25 - 20:45LHR-SEA

31h 20m1 stop

£403Icelandair

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Sat, 25 Apr - Sat, 16 May

15:35 - 19:30SEA-LHR

20h 55m1 stop

13:05 - 20:45LHR-SEA

15h 40m1 stop

£403Icelandair

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Wed, 25 Mar - Wed, 8 Apr

15:45 - 11:55SEA-LHR

12h 10m1 stop

13:05 - 20:45LHR-SEA

15h 40m1 stop

£404Icelandair

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Tue, 7 Apr - Tue, 21 Apr

15:35 - 10:55SEA-LHR

12h 20m1 stop

21:25 - 20:45LHR-SEA

31h 20m1 stop

£405Icelandair

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Sat, 28 Mar - Sun, 12 Apr

12:45 - 17:40SEA-LHR

20h 55m2 stops

06:40 - 22:23LHR-SEA

23h 43m2 stops

£417Scandinavian Airlines

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Thu, 4 Dec - Tue, 9 Dec

20:05 - 16:50SEA-LHR

12h 45m1 stop

08:50 - 18:20LHR-SEA

17h 30m1 stop

£422Aer Lingus

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Mon, 24 Nov - Wed, 26 Nov

14:35 - 21:05SEA-LHR

22h 30m2 stops

07:50 - 17:00LHR-SEA

17h 10m2 stops

£437Multiple Airlines

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Mon, 5 Jan - Mon, 19 Jan

14:35 - 21:05SEA-LHR

22h 30m2 stops

07:50 - 17:00LHR-SEA

17h 10m2 stops

£441Multiple Airlines

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Tue, 2 Dec - Tue, 9 Dec

18:50 - 12:20SEA-LHR

9h 30mdirect

14:55 - 16:55LHR-SEA

10h 00mdirect

£444British Airways

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Wed, 31 Dec - Thu, 5 Mar

Icelandair flights from Seattle to London Heathrow Airport

Our best Icelandair deals on Seattle to London Heathrow Airport flight tickets

Icelandair

21 Apr

SEA19:00Seattle/Tacoma Intl

17h 20m

1 stop

LHR20:20London Heathrow

5 May

LHR21:25London Heathrow

28h 25m

1 stop

SEA17:50Seattle/Tacoma Intl

£401

Find similar

Icelandair

25 Apr

SEA19:00Seattle/Tacoma Intl

17h 20m

1 stop

LHR20:20London Heathrow

16 May

LHR21:25London Heathrow

31h 20m

1 stop

SEA20:45Seattle/Tacoma Intl

£402

Find similar

Icelandair

25 Mar

SEA15:35Seattle/Tacoma Intl

20h 55m

1 stop

LHR19:30London Heathrow

8 Apr

LHR13:05London Heathrow

15h 40m

1 stop

SEA20:45Seattle/Tacoma Intl

£403

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Air France flights from Seattle to London Heathrow Airport

Our best Air France deals on Seattle to London Heathrow Airport flight tickets

Air France

3 Dec

SEA16:48Seattle/Tacoma Intl

9h 42m

LHR10:30London Heathrow

10 Dec

LHR06:20London Heathrow

15h 05m

1 stop

SEA13:25Seattle/Tacoma Intl

£438

Find similar

Air France

12 Nov

SEA16:48Seattle/Tacoma Intl

9h 42m

LHR10:30London Heathrow

26 Nov

LHR06:20London Heathrow

15h 00m

1 stop

SEA13:20Seattle/Tacoma Intl

£438

Find similar

Air France

7 Jan

SEA16:45Seattle/Tacoma Intl

9h 45m

LHR10:30London Heathrow

22 Jan

LHR06:20London Heathrow

13h 05m

1 stop

SEA11:25Seattle/Tacoma Intl

£445

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momondo Fare Finder

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

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Depart

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Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 21/4

19:00-20:20

1 stop17h 20m

London Heathrow

Tue 5/5

21:25-17:50

1 stop28h 25m

£401

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 25/4

19:00-20:20

1 stop17h 20m

London Heathrow

Sat 16/5

21:25-20:45

1 stop31h 20m

£402

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 25/3

15:35-19:30

1 stop20h 55m

London Heathrow

Wed 8/4

13:05-20:45

1 stop15h 40m

£403

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 7/4

15:45-11:55

1 stop12h 10m

London Heathrow

Tue 21/4

13:05-20:45

1 stop15h 40m

£404

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 28/3

15:35-10:55

1 stop12h 20m

London Heathrow

Sun 12/4

21:25-20:45

1 stop31h 20m

£405

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 4/12

12:45-17:40

2 stops20h 55m

London Heathrow

Tue 9/12

06:40-22:23

2 stops23h 43m

£417

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 24/11

20:05-16:50

1 stop12h 45m

London Heathrow

Wed 26/11

08:50-18:20

1 stop17h 30m

£422

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 5/1

14:35-21:05

2 stops22h 30m

London Heathrow

Mon 19/1

07:50-17:00

2 stops17h 10m

£437

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 2/12

14:35-21:05

2 stops22h 30m

London Heathrow

Tue 9/12

07:50-17:00

2 stops17h 10m

£441

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 31/12

18:50-12:20

Nonstop9h 30m

London Heathrow

Thu 5/3

14:55-16:55

Nonstop10h 00m

£444

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Showing 1-10 of 20 resultsSorted by cheapest first

How to get the cheapest flight ticket from Seattle to London Heathrow Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Delays

Other information

What is the cheapest month to fly to London Heathrow Airport?

In general, March is the cheapest month to fly from Seattle to London Heathrow Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around £521. The month of February is another great option to travel to London Heathrow Airport, with average flight prices from Seattle averaging around £531.

What is the cheapest day to depart on your flight to London Heathrow Airport?

On average, the least expensive day to fly to London Heathrow Airport from Seattle is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as £526. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Friday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Friday is £671.

What is the cheapest time of day to depart on your flight to London Heathrow Airport?

According to our data, the cheapest time of day to fly to London Heathrow Airport is at midday. momondo users have found flights departing from Seattle to London Heathrow Airport at midday for as low as £598. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying in the evening when prices are £656 on average. Flights to London Heathrow Airport from Seattle in the evening are generally more expensive because this time of day is more convenient for travellers’ schedules.

What is the cheapest Seattle/Tacoma Intl to London Heathrow flight route?

Fly from Seattle/Tacoma Intl to London Heathrow for the best Seattle/Tacoma Intl - London Heathrow flight prices

How far in advance should I book a flight to London Heathrow Airport?

You are more likely to see cheaper flights to London Heathrow Airport from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around £613 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Seattle for as low as £538 on momondo.

What cabin class options are available on Seattle/Tacoma Intl to London Heathrow flights?

There are 3 cabin classes available to choose from on Seattle/Tacoma Intl to London Heathrow flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Seattle to London Heathrow Airport flight prices changed over time?

As of November 2025, prices for Seattle to London Heathrow Airport flights are approximately 31% cheaper when compared to flights at the same time last year.

When to book flights from Seattle to London Heathrow Airport

Are you open to changing your travel dates? Check out the ideal times to fly from Seattle to London Heathrow Airport according to our flight data. Find out which month and days have the cheapest flights.

Estimated return price

Cheap Seattle to London Heathrow Airport (SEA to LHR) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Seattle to London Heathrow Airport

Best price found	£469
Fastest flight time	9h 15m
Direct flights	Every day

The best one-way flight to London Heathrow Airport from Seattle in the past 72 hours is £469. The best return flight deal from Seattle to London Heathrow Airport found on momondo in the last 72 hours is £498.

The fastest flight from Seattle to London Heathrow Airport takes 9h 15m

Direct flights go from Seattle to London Heathrow Airport every day.

Search flight deals

How far is Seattle/Tacoma Intl to London Heathrow by plane?
The distance between Seattle/Tacoma Intl and London Heathrow is about 4774.1 mi. By plane, this route typically takes 9h 30m.
When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?
Prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport are refreshed on a daily basis.
How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?
There are 2 operators available for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport as of November 2025.
How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Heathrow Airport?
Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to London Heathrow Airport.
What documentation or ID do you need to fly to London Heathrow Airport?
The travel and health documents you'll need for your trip to London Heathrow Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London Heathrow Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from Seattle to London Heathrow Airport?
Based on momondo bookings for flights between Seattle and London Heathrow Airport, the leading plane model is Boeing 787-10 Dreamliner, making up 24.89% of the total bookings. Other popular models include Airbus A330-200 with 16.87%, Boeing 787-9 Dreamliner with 14.64%, and Airbus A330-900neo with 12.30%.
What is the most popular airline from Seattle to London Heathrow Airport?
momondo data reveals that the most frequently booked airline on the route from Seattle to London Heathrow Airport is Virgin Atlantic, representing 71% of all bookings. The subsequent popular airline is British Airways at 29%.

Best airlines flying from Seattle to London Heathrow Airport

Compare and see reviews for airlines that fly from Seattle to London Heathrow Airport with momondo

Airline	Rating	Free Cancellation	Price
British Airways	PriceFrom £362	Free Cancellation	Rating 6.7 7,500 reviews		Search British Airways flights
Virgin Atlantic	PriceFrom £377	Free Cancellation	Rating 7.5 672 reviews		Search Virgin Atlantic flights

Virgin Atlantic Flights From Seattle to London Heathrow Airport
Across 10 Virgin Atlantic flights from Seattle to London Heathrow Airport this week, the average price was £629, with the best Virgin Atlantic deals starting from £377 round-trip. 672 users have rated Virgin Atlantic on momondo, with an average score of 7.5/10.
British Airways Flights From Seattle to London Heathrow Airport
Another popular option for Seattle to London Heathrow Airport flights is British Airways (6.7/10, 7,500 ratings). British Airways flies from Seattle to London Heathrow Airport around 11 times per week, with deals starting from £362 round-trip and rising to an average price of around £608.

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Why use momondo?

Why should I use momondo to find a flight deal from Seattle to London?

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to London from Seattle.

Can I find flights from Seattle to London with flexible booking policies on momondo?

Flights from Seattle to London with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

How can momondo help me find flights from Seattle to London?

momondo helps you find the best flight between Seattle and London by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

I’m not ready to book a flight from Seattle to London right now. Can momondo alert me if prices change?

If you are simply researching potential flights to London, momondo offers a useful price alert feature which will track prices for flights to London from Seattle and alert you when they change.

An easier way to manage your London Heathrow Airport trip

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Cheap flights from Seattle to London from £270

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to London departing on 29/12. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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Icelandair flights from Seattle to London Heathrow Airport

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Our best Air France deals on Seattle to London Heathrow Airport flight tickets

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

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How to get the cheapest flight ticket from Seattle to London Heathrow Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to London Heathrow Airport?

What is the cheapest day to depart on your flight to London Heathrow Airport?

What is the cheapest time of day to depart on your flight to London Heathrow Airport?

What is the cheapest Seattle/Tacoma Intl to London Heathrow flight route?

Fly from Seattle/Tacoma Intl to London Heathrow for the best Seattle/Tacoma Intl - London Heathrow flight prices

How far in advance should I book a flight to London Heathrow Airport?

What cabin class options are available on Seattle/Tacoma Intl to London Heathrow flights?

There are 3 cabin classes available to choose from on Seattle/Tacoma Intl to London Heathrow flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Seattle to London Heathrow Airport flight prices changed over time?

As of November 2025, prices for Seattle to London Heathrow Airport flights are approximately 31% cheaper when compared to flights at the same time last year.

What is the cheapest airline that flies from Seattle/Tacoma Intl to London Heathrow?

Icelandair, Scandinavian Airlines, and Lufthansa are the most popular carriers operating from Seattle/Tacoma Intl to London Heathrow

How often are flights from Seattle to London delayed?

Historically, on average around 17% of flights between Seattle and London have experienced a delay on any given week. The average delay length over the past 12 months has been 131 minutes.

What is the most punctual flight time for Seattle to London flights?

Generally, flights departing in the early afternoon tend to experience fewer delays. Flights departing in the evening have, in the past, seen delays more frequently in comparison.

What day of the week experiences the fewest flight delays on this route?

Friday is statistically the day of the week that experiences the fewest delays on this flight route. Sunday has historically seen more delays on average compared to the rest of the week.

Which airline has the best punctuality record on Seattle to London flights?

According to our data, La Costena have had the fewest delays on this route over the last 12 months, with no flights being classified as delayed.

How many flights depart from Seattle to London Heathrow Airport on average per day?

As of November 2025, 11 flights take off from Seattle and land in London Heathrow Airport each day. The most common flight departure time for this route is 16:00, with 54% of daily flights taking off in the afternoon.

How many flights depart from Seattle to London Heathrow Airport on average per week?

77 flights are operational weekly from Seattle to London Heathrow Airport as of November 2025. The most popular departure day for this route is Mon, with 19% of flights per week taking off on this day.

When to book flights from Seattle to London Heathrow Airport

Cheap Seattle to London Heathrow Airport (SEA to LHR) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Seattle to London Heathrow Airport

Best price found

Fastest flight time

Direct flights

How far is Seattle/Tacoma Intl to London Heathrow by plane?

When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?

How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?

How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Heathrow Airport?

What documentation or ID do you need to fly to London Heathrow Airport?

What is the most popular plane model from Seattle to London Heathrow Airport?

What is the most popular airline from Seattle to London Heathrow Airport?

Best airlines flying from Seattle to London Heathrow Airport

Compare and see reviews for airlines that fly from Seattle to London Heathrow Airport with momondo

Virgin Atlantic Flights From Seattle to London Heathrow Airport

British Airways Flights From Seattle to London Heathrow Airport

Travelling to a place near London?

Why use momondo?

Why should I use momondo to find a flight deal from Seattle to London?

Can I find flights from Seattle to London with flexible booking policies on momondo?

How can momondo help me find flights from Seattle to London?

I’m not ready to book a flight from Seattle to London right now. Can momondo alert me if prices change?

An easier way to manage your London Heathrow Airport trip

We make it super easy to schedule, organise and travel with friends or family. Trips is free – and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to London

Popular Cities in the United Kingdom

Popular flights according to clicks in the last 7 days on momondo