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Cheap flights from Seattle to London from £193

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 12/10. 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

Icelandair Logo
19:00 - 11:55SEA-LHR
32h 55m1 stop
Icelandair Logo
21:25 - 20:40LHR-SEA
31h 15m1 stop
£374Icelandair
Find Deal
ma., 22 sep. - ma., 6 okt.
Delta Logo
15:15 - 13:30SEA-LHR
14h 15m1 stop
Delta Logo
06:15 - 17:40LHR-SEA
19h 25m1 stop
£375Delta
Find Deal
sø., 21 sep. - ti., 7 okt.
British Airways Logo
20:20 - 13:40SEA-LHR
9h 20mdirect
British Airways Logo
09:25 - 11:30LHR-SEA
10h 05mdirect
£378British Airways
Find Deal
ti., 14 okt. - ti., 4 nov.
British Airways Logo
13:30 - 06:50SEA-LHR
9h 20mdirect
British Airways Logo
09:50 - 11:35LHR-SEA
9h 45mdirect
£379British Airways
Find Deal
ma., 6 okt. - to., 16 okt.
Virgin Atlantic Logo
15:15 - 13:30SEA-LHR
14h 15m1 stop
Virgin Atlantic Logo
06:15 - 11:15LHR-SEA
13h 00m1 stop
£379Virgin Atlantic
Find Deal
sø., 21 sep. - ti., 7 okt.
Logo
13:30 - 09:50SEA-LHR
12h 20m1 stop
Logo
17:25 - 19:50LHR-SEA
10h 25mdirect
£385
Find Deal
ti., 23 sep. - ti., 30 sep.
Logo
07:00 - 06:30SEA-LHR
15h 30m2 stops
Logo
08:30 - 19:31LHR-SEA
19h 01m2 stops
£390
Find Deal
ti., 23 sep. - ti., 30 sep.
United Airlines Logo
20:00 - 11:50SEA-LHR
31h 50m1 stop
United Airlines Logo
11:05 - 20:37LHR-SEA
41h 32m2 stops
£391United Airlines
Find Deal
ma., 2 feb. - ma., 9 feb.
United Airlines Logo
07:00 - 06:20SEA-LHR
15h 20m1 stop
United Airlines Logo
11:05 - 18:49LHR-SEA
39h 44m2 stops
£394United Airlines
Find Deal
ti., 7 okt. - ma., 13 okt.
Virgin Atlantic Logo
20:25 - 14:15SEA-LHR
9h 50mdirect
Virgin Atlantic Logo
12:20 - 15:45LHR-SEA
10h 25mdirect
£400Virgin Atlantic
Find Deal
to., 23 okt. - to., 30 okt.

Icelandair flights from Seattle to London Heathrow Airport

Our best Icelandair deals on Seattle to London Heathrow Airport flight tickets
Icelandair
22 Sept
SEA19:00Seattle/Tacoma Intl
32h 55m
1 stop
LHR11:55London Heathrow
6 Oct
LHR21:25London Heathrow
31h 15m
1 stop
SEA20:40Seattle/Tacoma Intl
£374
Find similar
Icelandair
25 Feb
SEA14:35Seattle/Tacoma Intl
12h 15m
1 stop
LHR10:50London Heathrow
18 Mar
LHR12:15London Heathrow
12h 45m
1 stop
SEA18:00Seattle/Tacoma Intl
£380
Find similar
Icelandair
3 Oct
SEA15:45Seattle/Tacoma Intl
12h 10m
1 stop
LHR11:55London Heathrow
15 Oct
LHR13:05London Heathrow
12h 45m
1 stop
SEA17:50Seattle/Tacoma Intl
£381
Find similar

United Airlines flights from Seattle to London Heathrow Airport

Our best United Airlines deals on Seattle to London Heathrow Airport flight tickets
United Airlines
2 Feb
SEA20:00Seattle/Tacoma Intl
31h 50m
1 stop
LHR11:50London Heathrow
9 Feb
LHR11:05London Heathrow
41h 32m
2 stops
SEA20:37Seattle/Tacoma Intl
£391
Find similar
United Airlines
7 Oct
SEA07:00Seattle/Tacoma Intl
15h 20m
1 stop
LHR06:20London Heathrow
13 Oct
LHR11:05London Heathrow
39h 44m
2 stops
SEA18:49Seattle/Tacoma Intl
£394
Find similar
United Airlines
10 Oct
SEA18:50Seattle/Tacoma Intl
14h 15m
1 stop
LHR17:05London Heathrow
12 Oct
LHR06:30London Heathrow
13h 25m
1 stop
SEA11:55Seattle/Tacoma Intl
£395
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 12 september 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

ma. 22/9

19:00-11:55

1 stop32h 55m

London Heathrow

ma. 6/10

21:25-20:40

1 stop31h 15m

£374

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

sø. 21/9

15:15-13:30

1 stop14h 15m

London Heathrow

ti. 7/10

06:15-17:40

1 stop19h 25m

£375

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ti. 14/10

20:20-13:40

Nonstop9h 20m

London Heathrow

ti. 4/11

09:25-11:30

Nonstop10h 05m

£378

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ma. 6/10

13:30-06:50

Nonstop9h 20m

London Heathrow

to. 16/10

09:50-11:35

Nonstop9h 45m

£379

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

sø. 21/9

15:15-13:30

1 stop14h 15m

London Heathrow

ti. 7/10

06:15-11:15

1 stop13h 00m

£379

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ti. 23/9

13:30-09:50

1 stop12h 20m

London Heathrow

ti. 30/9

17:25-19:50

Nonstop10h 25m

£385

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ti. 23/9

07:00-06:30

2 stops15h 30m

London Heathrow

ti. 30/9

08:30-19:31

2 stops19h 01m

£390

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ma. 2/2

20:00-11:50

1 stop31h 50m

London Heathrow

ma. 9/2

11:05-20:37

2 stops41h 32m

£391

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

ti. 7/10

07:00-06:20

1 stop15h 20m

London Heathrow

ma. 13/10

11:05-18:49

2 stops39h 44m

£394

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

to. 23/10

20:25-14:15

Nonstop9h 50m

London Heathrow

to. 30/10

12:20-15:45

Nonstop10h 25m

£400

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 £504. The month of April is another great option to travel to London Heathrow Airport, with average flight prices from Seattle averaging around £516.

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 £501. 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 £679.

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 £578. 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 £645 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 £591 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 £512 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 September 2025, prices for Seattle to London Heathrow Airport flights are approximately 12% 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

£352

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 £352. The best return flight deal from Seattle to London Heathrow Airport found on momondo in the last 72 hours is £531.
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 20m.

  • 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 £346Free CancellationRating
7.2
1,271 reviews
Search Aer Lingus flights
British AirwaysPriceFrom £350Free CancellationRating
6.6
7,361 reviews
Search British Airways flights
Virgin AtlanticPriceFrom £365Free CancellationRating
7.4
664 reviews
Search Virgin Atlantic flights
IcelandairPriceFrom £407Free CancellationRating
7.0
546 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 £832, with the best Virgin Atlantic deals starting from £494 round-trip. 664 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, 1,271 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
Luton
Milton Keynes
Maidstone
Northampton
Gatwick
Slough
Swindon
Canterbury
Stratford-upon-Avon
Southend-on-Sea
Ipswich
Ilford
Guildford
Swanage
Poole
Colchester
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Dover

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.

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