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Cheap flights from Seattle to London from £263

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 10/12. 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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Cheap return flights

Enter your travel dates to find the best prices.
Icelandair Logo
14:35 - 19:30SEA-LHR
20h 55m1 stop
Icelandair Logo
12:15 - 17:00LHR-SEA
12h 45m1 stop
£387Icelandair
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Sun, 9 Nov - Tue, 25 Nov
Icelandair Logo
14:35 - 19:30SEA-LHR
20h 55m1 stop
Icelandair Logo
12:15 - 17:00LHR-SEA
12h 45m1 stop
£388Icelandair
Find Deal
Wed, 12 Nov - Wed, 19 Nov
Icelandair Logo
14:35 - 10:50SEA-LHR
12h 15m1 stop
Icelandair Logo
12:15 - 17:00LHR-SEA
12h 45m1 stop
£389Icelandair
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Mon, 17 Nov - Mon, 8 Dec
Alaska Airlines Logo
19:50 - 12:20SEA-LHR
9h 30mdirect
Alaska Airlines Logo
16:55 - 09:57LHR-SEA
25h 02m1 stop
£407Alaska Airlines
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Mon, 16 Mar - Sun, 5 Apr
Alaska Airlines Logo
13:55 - 12:20SEA-LHR
15h 25m1 stop
Alaska Airlines Logo
16:55 - 11:00LHR-SEA
26h 05m1 stop
£410Alaska Airlines
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Mon, 16 Mar - Sun, 5 Apr
Multiple Airlines Logo
14:35 - 21:05SEA-LHR
22h 30m2 stops
Multiple Airlines Logo
07:50 - 17:00LHR-SEA
17h 10m2 stops
£411Multiple Airlines
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Tue, 18 Nov - Tue, 25 Nov
Multiple Airlines Logo
10:05 - 11:50SEA-LHR
17h 45m1 stop
Multiple Airlines Logo
06:35 - 19:16LHR-SEA
20h 41m2 stops
£426Multiple Airlines
Find Deal
Sun, 9 Nov - Tue, 25 Nov
Lufthansa Logo
15:10 - 13:00SEA-LHR
13h 50m1 stop
Lufthansa Logo
06:30 - 12:10LHR-SEA
13h 40m1 stop
£434Lufthansa
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Wed, 3 Dec - Tue, 16 Dec
SWISS Logo
15:37 - 19:15SEA-LHR
19h 38m2 stops
SWISS Logo
09:00 - 22:28LHR-SEA
21h 28m2 stops
£443SWISS
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Wed, 12 Nov - Thu, 20 Nov
SWISS Logo
14:40 - 19:15SEA-LHR
20h 35m2 stops
SWISS Logo
20:05 - 23:44LHR-SEA
35h 39m2 stops
£444SWISS
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Wed, 12 Nov - Wed, 19 Nov

Icelandair flights from Seattle to London Heathrow Airport

Our best Icelandair deals on Seattle to London Heathrow Airport flight tickets
Icelandair
9 Nov
SEA14:35Seattle/Tacoma Intl
20h 55m
1 stop
LHR19:30London Heathrow
25 Nov
LHR12:15London Heathrow
12h 45m
1 stop
SEA17:00Seattle/Tacoma Intl
£387
Find similar
Icelandair
12 Nov
SEA14:35Seattle/Tacoma Intl
20h 55m
1 stop
LHR19:30London Heathrow
19 Nov
LHR12:15London Heathrow
12h 45m
1 stop
SEA17:00Seattle/Tacoma Intl
£388
Find similar
Icelandair
17 Nov
SEA14:35Seattle/Tacoma Intl
12h 15m
1 stop
LHR10:50London Heathrow
8 Dec
LHR12:15London Heathrow
12h 45m
1 stop
SEA17:00Seattle/Tacoma Intl
£389
Find similar

Alaska Airlines flights from Seattle to London Heathrow Airport

Our best Alaska Airlines deals on Seattle to London Heathrow Airport flight tickets
Alaska Airlines
16 Mar
SEA19:50Seattle/Tacoma Intl
9h 30m
LHR12:20London Heathrow
5 Apr
LHR16:55London Heathrow
25h 02m
1 stop
SEA09:57Seattle/Tacoma Intl
£407
Find similar
Alaska Airlines
16 Mar
SEA13:55Seattle/Tacoma Intl
15h 25m
1 stop
LHR12:20London Heathrow
5 Apr
LHR16:55London Heathrow
26h 05m
1 stop
SEA11:00Seattle/Tacoma Intl
£410
Find similar
Alaska Airlines
1 Jan
SEA06:00Seattle/Tacoma Intl
22h 20m
1 stop
LHR12:20London Heathrow
8 Jan
LHR14:55London Heathrow
10h 00m
SEA16:55Seattle/Tacoma Intl
£417
Find similar

momondo Fare Finder

 
Customise your flight search to find flights from Seattle to London Heathrow Airport 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, momondo users made 279,928 searches. Data last updated 10 October 2025.
Use the filters below to find and compare flights from Seattle to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 9/11

14:35-19:30

1 stop20h 55m

London Heathrow

Tue 25/11

12:15-17:00

1 stop12h 45m

£387

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 12/11

14:35-19:30

1 stop20h 55m

London Heathrow

Wed 19/11

12:15-17:00

1 stop12h 45m

£388

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 17/11

14:35-10:50

1 stop12h 15m

London Heathrow

Mon 8/12

12:15-17:00

1 stop12h 45m

£389

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 16/3

19:50-12:20

Nonstop9h 30m

London Heathrow

Sun 5/4

16:55-09:57

1 stop25h 02m

£407

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 16/3

13:55-12:20

1 stop15h 25m

London Heathrow

Sun 5/4

16:55-11:00

1 stop26h 05m

£410

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 18/11

14:35-21:05

2 stops22h 30m

London Heathrow

Tue 25/11

07:50-17:00

2 stops17h 10m

£411

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 9/11

10:05-11:50

1 stop17h 45m

London Heathrow

Tue 25/11

06:35-19:16

2 stops20h 41m

£426

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 3/12

15:10-13:00

1 stop13h 50m

London Heathrow

Tue 16/12

06:30-12:10

1 stop13h 40m

£434

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 12/11

15:37-19:15

2 stops19h 38m

London Heathrow

Thu 20/11

09:00-22:28

2 stops21h 28m

£443

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 12/11

14:40-19:15

2 stops20h 35m

London Heathrow

Wed 19/11

20:05-23:44

2 stops35h 39m

£444

Flights are sorted by cheapest return flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to London from

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?

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 £514. The month of September is another great option to travel to London Heathrow Airport, with average flight prices from Seattle averaging around £522.

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 £516. 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 £691.

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 £588. 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 £648 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 £602 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 £529 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 October 2025, prices for Seattle to London Heathrow Airport flights are approximately 43% 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

£294

Fastest flight time

9h 20m

Direct flights

Every day
The best one-way flight to London Heathrow Airport from Seattle in the past 72 hours is £294. The best return flight deal from Seattle to London Heathrow Airport found on momondo in the last 72 hours is £501.
The fastest flight from Seattle to London Heathrow Airport takes 9h 20m
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?

  • 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?

  • 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
Airline
Rating
Free Cancellation
Price
Aer LingusPriceFrom £352Free CancellationRating
7.2
1,324 reviews
Search Aer Lingus flights
British AirwaysPriceFrom £356Free CancellationRating
6.7
7,446 reviews
Search British Airways flights
Virgin AtlanticPriceFrom £370Free CancellationRating
7.4
665 reviews
Search Virgin Atlantic flights
IcelandairPriceFrom £414Free CancellationRating
7.0
551 reviews
Search Icelandair flights

  • Virgin Atlantic Flights From Seattle to London Heathrow Airport

    Across 14 Virgin Atlantic flights from Seattle to London Heathrow Airport this week, the average price was £839, with the best Virgin Atlantic deals starting from £492 round-trip. 665 users have rated Virgin Atlantic on momondo, with an average score of 7.4/10.

  • Aer Lingus Flights From Seattle to London Heathrow Airport

    Another popular option for Seattle to London Heathrow Airport flights is Aer Lingus (7.2/10, 1,324 ratings). Aer Lingus flies from Seattle to London Heathrow Airport around 13 times per week, with deals starting from £468 round-trip and rising to an average price of around £687.

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Eastbourne
Milton Keynes
Luton
Maidstone
Gatwick
Northampton
Slough
Swindon
Canterbury
Stratford-upon-Avon
Southend-on-Sea
Ipswich
Ilford
Guildford
Poole
Swanage
Colchester
Dover
Hayes
Chelmsford

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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