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

As of December 2025, there are 67 flights per week flying from Seattle to London. The most common day of the week flights depart is Sat, with 24% of flights taking off on this day.

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

WestJet and United Airlines are the most popular carriers operating from Seattle/Tacoma Intl to London

How often are flights from Seattle to London delayed?

Historically, on average around 16% 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 123 minutes.

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

According to our data, Virgin Atlantic has had the least delays on this route over the last 12 months, with about 6% of their flights experiencing any sort of delay.

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

9 flights are operational daily from Seattle to London as of December 2025. The most popular departure time for this route is 4:00p.m., with 61% of flights per day taking off in the afternoon.

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 at night have, in the past, seen delays more frequently in comparison.

Which airlines fly to London?

Virgin Atlantic, British Airways and Iberia are the top three most popular airlines that fly to London from Seattle according to our data. Virgin Atlantic is the first choice among our users, with 47% of people opting to fly with this airline when travelling to London. Keep in mind that there are 4 different airlines that fly to London on a routine basis, so you have a few additional options to choose from.

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

Tuesday 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.

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

Prices for flights from Seattle/Tacoma Intl Airport to London are updated daily.

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

As of December 2025, there are 4 operators available to choose from for flights from Seattle/Tacoma Intl Airport to London.

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

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.

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

The travel and health documents you'll need for your trip to London 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. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

C$ 493 Cheap Flights from Seattle to London in 2025/26

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Cheap round-trip flights

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3:35 p.m. - 10:55 a.m.

SEA

LGW

12h 20m1 stop

11:55 a.m. - 6:00 p.m.

LGW

SEA

13h 05m1 stop

C$ 829Icelandair

Wed, 18 Mar - Mon, 23 Mar

2:35 p.m. - 10:50 a.m.

SEA

LHR

12h 15m1 stop

12:15 p.m. - 5:00 p.m.

LHR

SEA

12h 45m1 stop

C$ 832Icelandair

Wed, 7 Jan - Wed, 21 Jan

3:35 p.m. - 10:50 a.m.

SEA

LHR

12h 15m1 stop

12:15 p.m. - 6:00 p.m.

LHR

SEA

12h 45m1 stop

C$ 833Icelandair

Thu, 12 Mar - Fri, 20 Mar

3:40 p.m. - 11:50 a.m.

SEA

LHR

12h 10m1 stop

7:40 a.m. - 1:20 p.m.

LHR

SEA

13h 40m1 stop

C$ 844Lufthansa

Thu, 19 Feb - Wed, 25 Feb

4:55 p.m. - 10:30 a.m.

SEA

LHR

9h 35mdirect

11:45 a.m. - 11:40 a.m.

LHR

SEA

31h 55m1 stop

C$ 845Delta

Mon, 16 Feb - Mon, 23 Feb

6:25 p.m. - 11:55 a.m.

SEA

LHR

9h 30mdirect

6:30 a.m. - 11:35 a.m.

LHR

SEA

13h 05m1 stop

C$ 847KLM

Tue, 17 Feb - Sun, 1 Mar

10:55 p.m. - 6:25 a.m.

SEA

LHR

23h 30m1 stop

6:30 a.m. - 11:50 a.m.

LHR

SEA

13h 20m1 stop

C$ 848Delta

Sun, 11 Jan - Sat, 24 Jan

5:30 a.m. - 10:00 a.m.

SEA

LHR

21h 30m1 stop

8:40 a.m. - 12:35 p.m.

LHR

SEA

34h 55m1 stop

C$ 852Delta

Sat, 14 Mar - Mon, 23 Mar

4:45 p.m. - 10:30 a.m.

SEA

LHR

9h 45mdirect

6:20 a.m. - 1:20 p.m.

LHR

SEA

15h 00m1 stop

C$ 854Delta

Thu, 22 Jan - Sun, 1 Feb

8:10 a.m. - 11:20 a.m.

SEA

LHR

20h 10m1 stop

6:35 a.m. - 2:20 p.m.

LHR

SEA

14h 45m1 stop

C$ 855United Airlines

Fri, 13 Mar - Wed, 25 Mar

United Airlines flights from Seattle to London

Our best United Airlines deals on Seattle to London flight tickets

United Airlines

13 Mar

SEA8:10 a.m.Seattle/Tacoma Intl

20h 10m

1 stop

LHR11:20 a.m.London Heathrow

25 Mar

LHR6:35 a.m.London Heathrow

14h 45m

1 stop

SEA2:20 p.m.Seattle/Tacoma Intl

C$ 855

Find similar

United Airlines

19 Mar

SEA10:05 a.m.Seattle/Tacoma Intl

18h 45m

1 stop

LHR11:50 a.m.London Heathrow

24 Mar

LHR6:30 a.m.London Heathrow

13h 40m

1 stop

SEA1:10 p.m.Seattle/Tacoma Intl

C$ 861

Find similar

United Airlines

19 Feb

SEA7:00 a.m.Seattle/Tacoma Intl

19h 15m

2 stops

LHR10:15 a.m.London Heathrow

24 Feb

LHR6:50 a.m.London Heathrow

20h 13m

2 stops

SEA7:03 p.m.Seattle/Tacoma Intl

C$ 863

Find similar

KLM flights from Seattle to London

Our best KLM deals on Seattle to London flight tickets

KLM

17 Feb

SEA6:25 p.m.Seattle/Tacoma Intl

9h 30m

LHR11:55 a.m.London Heathrow

1 Mar

LHR6:30 a.m.London Heathrow

13h 05m

1 stop

SEA11:35 a.m.Seattle/Tacoma Intl

C$ 847

Find similar

KLM

19 Feb

SEA8:00 a.m.Seattle/Tacoma Intl

15h 05m

1 stop

LHR7:05 a.m.London Heathrow

23 Feb

LHR6:30 a.m.London Heathrow

13h 10m

1 stop

SEA11:40 a.m.Seattle/Tacoma Intl

C$ 852

Find similar

KLM

5 Apr

SEA5:35 p.m.Seattle/Tacoma Intl

12h 15m

1 stop

LHR1:50 p.m.London Heathrow

15 Apr

LHR5:25 p.m.London Heathrow

10h 20m

SEA7:45 p.m.Seattle/Tacoma Intl

C$ 918

Find similar

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 18/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Mon 23/3

11:55 a.m.-6:00 p.m.

1 stop13h 05m

C$ 829

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 7/1

2:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

Wed 21/1

12:15 p.m.-5:00 p.m.

1 stop12h 45m

C$ 832

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 12/3

3:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

Fri 20/3

12:15 p.m.-6:00 p.m.

1 stop12h 45m

C$ 833

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 19/2

3:40 p.m.-11:50 a.m.

1 stop12h 10m

London Heathrow

Wed 25/2

7:40 a.m.-1:20 p.m.

1 stop13h 40m

C$ 844

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 16/2

4:55 p.m.-10:30 a.m.

Nonstop9h 35m

London Heathrow

Mon 23/2

11:45 a.m.-11:40 a.m.

1 stop31h 55m

C$ 845

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 17/2

6:25 p.m.-11:55 a.m.

Nonstop9h 30m

London Heathrow

Sun 1/3

6:30 a.m.-11:35 a.m.

1 stop13h 05m

C$ 847

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 11/1

10:55 p.m.-6:25 a.m.

1 stop23h 30m

London Heathrow

Sat 24/1

6:30 a.m.-11:50 a.m.

1 stop13h 20m

C$ 848

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 14/3

5:30 a.m.-10:00 a.m.

1 stop21h 30m

London Heathrow

Mon 23/3

8:40 a.m.-12:35 p.m.

1 stop34h 55m

C$ 852

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 22/1

4:45 p.m.-10:30 a.m.

Nonstop9h 45m

London Heathrow

Sun 1/2

6:20 a.m.-1:20 p.m.

1 stop15h 00m

C$ 854

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 13/3

8:10 a.m.-11:20 a.m.

1 stop20h 10m

London Heathrow

Wed 25/3

6:35 a.m.-2:20 p.m.

1 stop14h 45m

C$ 855

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Showing 1-10 of 20 resultsSorted by cheapest first

How to get the cheapest flight ticket from Seattle to London

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?

In general, November is the cheapest month to fly from Seattle to London. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around C$ 890. If you aren’t able to travel to London during the month of November, then flying in October is also cheap. Prices for this month can be found on momondo for an average of C$ 891.

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

According to our data, Sunday is the cheapest day to fly to London from Seattle. The lowest ticket price found for a Sunday departure recently was C$ 1,038. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. When flying out on a Friday, the most expensive travel day of the week, you can expect to see flight prices from Seattle to London for around C$ 1,181.

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

Our most recent data shows that the best time of day to fly to London is in the morning. Flights from Seattle to London during this time can be as low as C$ 941. In the afternoon is when there is more demand to fly to London, so prices are often more expensive at around C$ 1,176 per ticket.

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

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

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

You are more likely to see cheaper flights to London from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around C$ 1,094 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London from Seattle for as low as C$ 953 on momondo.

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

There are 4 cabin classes available to choose from on Seattle/Tacoma Intl to London flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Seattle to London flights?

You could potentially save up to 12% on your flight if you consider stops on a Seattle to London flight.

How have Seattle to London flight prices changed over time?

As of December 2025, prices for Seattle to London flights are approximately 8% cheaper when compared to flights at the same time last year.

When to book flights from Seattle to London

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

Estimated round-trip price

Cheap Seattle to London (SEA to LON) flight deals and tips

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

Best price found	C$ 473
Fastest flight time	9h 30m
Direct flights	Every day
Airports in London	6 airports

The best one-way flight to London from Seattle in the past 72 hours is C$ 473. The best round-trip flight deal from Seattle to London found on momondo in the last 72 hours is C$ 978.

The fastest flight from Seattle to London takes 9h 30m

Direct flights go from Seattle to London every day.

There are 6 airports in London. From Seattle there are direct flights to London Heathrow (LHR).

Search flight deals

How far is Seattle/Tacoma Intl to London by plane?
The straight-line distance from Seattle/Tacoma Intl to London is 7694.7 km. 9h 30m is a normal flight duration for this route.
When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London?
Prices for flights from Seattle/Tacoma Intl Airport to London are updated daily.
How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London?
As of December 2025, there are 4 operators available to choose from for flights from Seattle/Tacoma Intl Airport to London.
How old do you have to be to fly from Seattle/Tacoma Intl Airport to London?
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.
What documentation or ID do you need to fly to London?
The travel and health documents you'll need for your trip to London 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. 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?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from Seattle to London is Boeing 787-10 Dreamliner (25.70% of total bookings). The next most popular plane models are Boeing 787-9 Dreamliner (25.09%), Airbus A330-200 (20.71%), and Boeing 777 (8.56%).
What is the most popular airline from Seattle to London?
Based on momondo bookings for this flight route, the most popular airline on flight routes from Seattle to London is British Airways (27% of total bookings). The next most popular airlines are Icelandair (21%), Virgin Atlantic (18%), and Air France (17%).

Best airlines flying from Seattle to London

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

Airline	Rating	Free Cancellation	Price
Iberia	PriceFrom C$ 625	Free Cancellation	Rating 7.0 3,051 reviews	Search Iberia flights
Icelandair	PriceFrom C$ 650	Free Cancellation	Rating 7.0 590 reviews	Search Icelandair flights
Virgin Atlantic	PriceFrom C$ 695	Free Cancellation	Rating 7.5 675 reviews	Search Virgin Atlantic flights
British Airways	PriceFrom C$ 699	Free Cancellation	Rating 6.7 7,575 reviews	Search British Airways flights

Virgin Atlantic Flights From Seattle to London
The lowest priced Virgin Atlantic flight from Seattle to London from the last 72 hours was C$ 695. Generally, Virgin Atlantic has 8 flights on this route every week with an average price of C$ 997. Virgin Atlantic is rated 7.5/10 by our users.
Iberia Flights From Seattle to London
C$ 625 is the best Iberia flight deal from Seattle to London found on momondo over the last 72 hours. The average Iberia ticket price found was closer to C$ 855, however, with flight time and availability significantly affecting the price. Iberia (7.0/10 from 3,051 user reviews) flies into London from Seattle 3 times in an average week so prices can vary.

Hounslow

Ipswich

Dartford

Gatwick

Ilford

Chelmsford

Wokingham

Slough

Feltham

Hayes

Uxbridge

Wembley

Waterlooville

Newport

Basingstoke

Milton Keynes

Dover

Worthing

Maidstone

Woking

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Seattle to London. momondo saves you time and could save you money on your trip.

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?

Yes. momondo can track prices for Seattle to London flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.

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Flights to Invernessfrom C$ 737

Cheap flights from Seattle to London from C$ 493

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 18/3. 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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United Airlines flights from Seattle to London

Our best United Airlines deals on Seattle to London flight tickets

KLM flights from Seattle to London

Our best KLM deals on Seattle to London flight tickets

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See travel insights to London from

How to get the cheapest flight ticket from Seattle to London

What is the cheapest month to fly to London?

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

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

Our most recent data shows that the best time of day to fly to London is in the morning. Flights from Seattle to London during this time can be as low as C$ 941. In the afternoon is when there is more demand to fly to London, so prices are often more expensive at around C$ 1,176 per ticket.

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

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

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

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

There are 4 cabin classes available to choose from on Seattle/Tacoma Intl to London flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Seattle to London flights?

You could potentially save up to 12% on your flight if you consider stops on a Seattle to London flight.

How have Seattle to London flight prices changed over time?

As of December 2025, prices for Seattle to London flights are approximately 8% cheaper when compared to flights at the same time last year.

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

WestJet and United Airlines are the most popular carriers operating from Seattle/Tacoma Intl to London

Which airlines fly to London?

How often are flights from Seattle to London delayed?

Historically, on average around 16% 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 123 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 at night have, in the past, seen delays more frequently in comparison.

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

Tuesday 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, Virgin Atlantic has had the least delays on this route over the last 12 months, with about 6% of their flights experiencing any sort of delay.

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

9 flights are operational daily from Seattle to London as of December 2025. The most popular departure time for this route is 4:00p.m., with 61% of flights per day taking off in the afternoon.

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

As of December 2025, there are 67 flights per week flying from Seattle to London. The most common day of the week flights depart is Sat, with 24% of flights taking off on this day.

When to book flights from Seattle to London

Cheap Seattle to London (SEA to LON) flight deals and tips

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

Best price found

Fastest flight time

Direct flights

Airports in London

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

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

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

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

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

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

What is the most popular airline from Seattle to London?

Best airlines flying from Seattle to London

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

Virgin Atlantic Flights From Seattle to London

Iberia Flights From Seattle to London

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 trip

We make it super easy to schedule, organize 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 the United Kingdom