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Cheap flights from Seattle to London from £128

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 30/9. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Cheap return flights

Scandinavian Airlines Logo
16:20 - 08:55SEA-LHR
56h 35m2 stops
Scandinavian Airlines Logo
07:05 - 14:00LHR-SEA
38h 55m2 stops
£225Scandinavian Airlines
Find Deal
Fri, 17 Oct - Tue, 21 Oct
Scandinavian Airlines Logo
16:20 - 17:40SEA-LHR
17h 20m1 stop
Scandinavian Airlines Logo
15:35 - 14:00LHR-SEA
30h 25m2 stops
£308Scandinavian Airlines
Find Deal
Sun, 5 Oct - Sat, 18 Oct
Aer Lingus Logo
19:35 - 19:25SEA-LHR
15h 50m1 stop
Aer Lingus Logo
09:50 - 17:50LHR-SEA
16h 00m1 stop
£340Aer Lingus
Find Deal
Wed, 13 Aug - Tue, 26 Aug
Aer Lingus Logo
19:35 - 15:55SEA-LHR
12h 20m1 stop
Aer Lingus Logo
13:25 - 17:50LHR-SEA
12h 25m1 stop
£341Aer Lingus
Find Deal
Mon, 18 Aug - Wed, 27 Aug
Icelandair Logo
15:45 - 20:20SEA-LHR
20h 35m1 stop
Icelandair Logo
12:15 - 17:00LHR-SEA
12h 45m1 stop
£355Icelandair
Find Deal
Wed, 1 Oct - Sun, 16 Nov
Icelandair Logo
15:45 - 11:55SEA-LHR
12h 10m1 stop
Icelandair Logo
13:05 - 17:50LHR-SEA
12h 45m1 stop
£356Icelandair
Find Deal
Tue, 14 Oct - Thu, 23 Oct
Virgin Atlantic Logo
20:25 - 14:15SEA-LHR
9h 50mdirect
Virgin Atlantic Logo
17:25 - 19:45LHR-SEA
10h 20mdirect
£363Virgin Atlantic
Find Deal
Mon, 4 Aug - Wed, 20 Aug
Virgin Atlantic Logo
20:25 - 14:15SEA-LHR
9h 50mdirect
Virgin Atlantic Logo
12:45 - 20:24LHR-SEA
15h 39m1 stop
£366Virgin Atlantic
Find Deal
Mon, 4 Aug - Wed, 20 Aug
British Airways Logo
20:20 - 13:40SEA-LHR
9h 20mdirect
British Airways Logo
16:30 - 18:20LHR-SEA
9h 50mdirect
£370British Airways
Find Deal
Sun, 3 Aug - Tue, 19 Aug
British Airways Logo
13:30 - 06:50SEA-LHR
9h 20mdirect
British Airways Logo
16:30 - 18:20LHR-SEA
9h 50mdirect
£372British Airways
Find Deal
Wed, 13 Aug - Tue, 26 Aug

Air Canada flights from Seattle to London Heathrow Airport

Our best Air Canada deals on Seattle to London Heathrow Airport flight tickets
Air Canada
8 Oct
SEA10:00Seattle/Tacoma Intl
19h 20m
1 stop
LHR13:20London Heathrow
15 Oct
LHR08:40London Heathrow
17h 56m
2 stops
SEA18:36Seattle/Tacoma Intl
Air Canada
12 Aug
SEA07:20Seattle/Tacoma Intl
15h 10m
1 stop
LHR06:30London Heathrow
27 Aug
LHR06:50London Heathrow
21h 51m
2 stops
SEA20:41Seattle/Tacoma Intl
Air Canada
13 Jul
SEA07:20Seattle/Tacoma Intl
15h 10m
1 stop
LHR06:30London Heathrow
15 Sept
LHR17:10London Heathrow
33h 26m
2 stops
SEA18:36Seattle/Tacoma Intl

Scandinavian Airlines flights from Seattle to London Heathrow Airport

Our best Scandinavian Airlines deals on Seattle to London Heathrow Airport flight tickets
Scandinavian Airlines
17 Oct
SEA16:20Seattle/Tacoma Intl
56h 35m
2 stops
LHR08:55London Heathrow
21 Oct
LHR07:05London Heathrow
38h 55m
2 stops
SEA14:00Seattle/Tacoma Intl
Scandinavian Airlines
5 Oct
SEA16:20Seattle/Tacoma Intl
17h 20m
1 stop
LHR17:40London Heathrow
18 Oct
LHR15:35London Heathrow
30h 25m
2 stops
SEA14:00Seattle/Tacoma Intl
Scandinavian Airlines
5 Oct
SEA16:20Seattle/Tacoma Intl
21h 20m
1 stop
LHR21:40London Heathrow
11 Oct
LHR06:40London Heathrow
39h 20m
2 stops
SEA14:00Seattle/Tacoma Intl

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 £501. The month of April is another great option to travel to London Heathrow Airport, with average flight prices from Seattle averaging around £510.

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 £510. 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 £815.

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 £605. 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 £595 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 £544 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 July 2025, prices for Seattle to London Heathrow Airport flights are approximately 36% 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

£128

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 £128. The best return flight deal from Seattle to London Heathrow Airport found on momondo in the last 72 hours is £225.
The fastest flight from Seattle to London Heathrow Airport takes 9h 20m
Direct flights go from Seattle to London Heathrow Airport every day.

  • 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
IcelandairPriceFrom £355Free CancellationRating
7.0
514 reviews
Search Icelandair flights
Virgin AtlanticPriceFrom £440Free CancellationRating
7.4
654 reviews
Search Virgin Atlantic flights
British AirwaysPriceFrom £449Free CancellationRating
6.6
7,093 reviews
Search British Airways 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 £863, with the best Virgin Atlantic deals starting from £601 round-trip. 654 users have rated Virgin Atlantic on momondo, with an average score of 7.4/10.

  • British Airways Flights From Seattle to London Heathrow Airport

    Another popular option for Seattle to London Heathrow Airport flights is British Airways (6.6/10, 7,093 ratings). British Airways flies from Seattle to London Heathrow Airport around 13 times per week, with deals starting from £613 round-trip and rising to an average price of around £989.


Travelling to a place near London?

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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.


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