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Cheap flights from Seattle to London from C$ 521

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 28/3. 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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Cheap round-trip flights

Enter your travel dates to find the best prices.
Icelandair Logo
2:35 p.m. - 10:50 a.m.SEA-LHR
12h 15m1 stop
Icelandair Logo
12:15 p.m. - 5:00 p.m.LHR-SEA
12h 45m1 stop
C$ 726Icelandair
Find Deal
Sat, 10 Jan - Mon, 19 Jan
Icelandair Logo
2:35 p.m. - 10:50 a.m.SEA-LHR
12h 15m1 stop
Icelandair Logo
8:35 p.m. - 5:00 p.m.LHR-SEA
28h 25m1 stop
C$ 729Icelandair
Find Deal
Mon, 24 Nov - Mon, 8 Dec
Icelandair Logo
3:35 p.m. - 10:55 a.m.SEA-LGW
12h 20m1 stop
Icelandair Logo
3:40 p.m. - 8:45 p.m.LGW-SEA
13h 05m1 stop
C$ 753Icelandair
Find Deal
Sun, 15 Mar - Tue, 31 Mar
Aer Lingus Logo
8:05 p.m. - 3:35 p.m.SEA-LHR
11h 30m1 stop
Aer Lingus Logo
12:10 p.m. - 6:20 p.m.LHR-SEA
14h 10m1 stop
C$ 779Aer Lingus
Find Deal
Mon, 24 Nov - Fri, 5 Dec
Delta Logo
4:48 p.m. - 10:30 a.m.SEA-LHR
9h 42mdirect
Delta Logo
6:20 a.m. - 11:25 a.m.LHR-SEA
13h 05m1 stop
C$ 806Delta
Find Deal
Wed, 12 Nov - Thu, 20 Nov
Delta Logo
4:48 p.m. - 10:30 a.m.SEA-LHR
9h 42mdirect
Delta Logo
6:30 a.m. - 11:50 a.m.LHR-SEA
13h 20m1 stop
C$ 807Delta
Find Deal
Wed, 10 Dec - Tue, 16 Dec
Finnair Logo
8:30 a.m. - 6:50 a.m.SEA-LHR
14h 20m1 stop
Finnair Logo
9:25 a.m. - 11:30 a.m.LHR-SEA
10h 05mdirect
C$ 817Finnair
Find Deal
Wed, 3 Dec - Tue, 20 Jan
British Airways Logo
6:50 p.m. - 12:20 p.m.SEA-LHR
9h 30mdirect
British Airways Logo
2:55 p.m. - 4:55 p.m.LHR-SEA
10h 00mdirect
C$ 827British Airways
Find Deal
Sun, 11 Jan - Fri, 23 Jan
Finnair Logo
6:50 p.m. - 12:20 p.m.SEA-LHR
9h 30mdirect
Finnair Logo
9:25 a.m. - 11:30 a.m.LHR-SEA
10h 05mdirect
C$ 828Finnair
Find Deal
Sun, 11 Jan - Tue, 20 Jan
British Airways Logo
6:50 p.m. - 12:20 p.m.SEA-LHR
9h 30mdirect
British Airways Logo
2:55 p.m. - 5:55 p.m.LHR-SEA
10h 00mdirect
C$ 850British Airways
Find Deal
Wed, 31 Dec - Tue, 17 Mar

Icelandair flights from Seattle to London

Our best Icelandair deals on Seattle to London flight tickets
Icelandair
10 Jan
SEA2:35 p.m.Seattle/Tacoma Intl
12h 15m
1 stop
LHR10:50 a.m.London Heathrow
19 Jan
LHR12:15 p.m.London Heathrow
12h 45m
1 stop
SEA5:00 p.m.Seattle/Tacoma Intl
C$ 726
Find similar
Icelandair
24 Nov
SEA2:35 p.m.Seattle/Tacoma Intl
12h 15m
1 stop
LHR10:50 a.m.London Heathrow
8 Dec
LHR8:35 p.m.London Heathrow
28h 25m
1 stop
SEA5:00 p.m.Seattle/Tacoma Intl
C$ 729
Find similar
Icelandair
15 Mar
SEA3:35 p.m.Seattle/Tacoma Intl
12h 20m
1 stop
LGW10:55 a.m.London Gatwick
31 Mar
LGW3:40 p.m.London Gatwick
13h 05m
1 stop
SEA8:45 p.m.Seattle/Tacoma Intl
C$ 753
Find similar

Finnair flights from Seattle to London

Our best Finnair deals on Seattle to London flight tickets
Finnair
3 Dec
SEA8:30 a.m.Seattle/Tacoma Intl
14h 20m
1 stop
LHR6:50 a.m.London Heathrow
20 Jan
LHR9:25 a.m.London Heathrow
10h 05m
SEA11:30 a.m.Seattle/Tacoma Intl
C$ 817
Find similar
Finnair
11 Jan
SEA6:50 p.m.Seattle/Tacoma Intl
9h 30m
LHR12:20 p.m.London Heathrow
20 Jan
LHR9:25 a.m.London Heathrow
10h 05m
SEA11:30 a.m.Seattle/Tacoma Intl
C$ 828
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Seattle to London 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 96,600 searches. Data last updated 30 October 2025.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 10/1

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

1 stop12h 15m

London Heathrow

Mon 19/1

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

1 stop12h 45m

C$ 726

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 24/11

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

1 stop12h 15m

London Heathrow

Mon 8/12

8:35 p.m.-5:00 p.m.

1 stop28h 25m

C$ 729

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Sun 15/3

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

1 stop12h 20m

London Gatwick

Tue 31/3

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 753

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 24/11

8:05 p.m.-3:35 p.m.

1 stop11h 30m

London Heathrow

Fri 5/12

12:10 p.m.-6:20 p.m.

1 stop14h 10m

C$ 779

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 12/11

4:48 p.m.-10:30 a.m.

Nonstop9h 42m

London Heathrow

Thu 20/11

6:20 a.m.-11:25 a.m.

1 stop13h 05m

C$ 806

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 10/12

4:48 p.m.-10:30 a.m.

Nonstop9h 42m

London Heathrow

Tue 16/12

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

1 stop13h 20m

C$ 807

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 3/12

8:30 a.m.-6:50 a.m.

1 stop14h 20m

London Heathrow

Tue 20/1

9:25 a.m.-11:30 a.m.

Nonstop10h 05m

C$ 817

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 11/1

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Fri 23/1

2:55 p.m.-4:55 p.m.

Nonstop10h 00m

C$ 827

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 11/1

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Tue 20/1

9:25 a.m.-11:30 a.m.

Nonstop10h 05m

C$ 828

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 31/12

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Tue 17/3

2:55 p.m.-5:55 p.m.

Nonstop10h 00m

C$ 850

Flights are sorted by cheapest round-trip 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

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?

In general, October 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$ 926. If you aren’t able to travel to London during the month of October, then flying in March is also cheap. Prices for this month can be found on momondo for an average of C$ 947.

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$ 1,176. 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 Wednesday, the most expensive travel day of the week, you can expect to see flight prices from Seattle to London for around C$ 1,283.

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$ 955. In the afternoon is when there is more demand to fly to London, so prices are often more expensive at around C$ 1,290 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$ 1,121 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$ 984 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 7% 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 October 2025, prices for Seattle to London flights are approximately 35% 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$ 480

Fastest flight time

9h 15m

Direct flights

Every day

Airports in London

1 airport
The best one-way flight to London from Seattle in the past 72 hours is C$ 480. The best round-trip flight deal from Seattle to London found on momondo in the last 72 hours is C$ 934.
The fastest flight from Seattle to London takes 9h 15m
Direct flights go from Seattle to London every day.
There is 1 airport near London: 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?

  • 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?

  • 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
Airline
Rating
Free Cancellation
Price
IcelandairPriceFrom C$ 616Free CancellationRating
7.1
562 reviews
Search Icelandair flights
Virgin AtlanticPriceFrom C$ 705Free CancellationRating
7.5
670 reviews
Search Virgin Atlantic flights
British AirwaysPriceFrom C$ 709Free CancellationRating
6.7
7,487 reviews
Search British Airways flights
IberiaPriceFrom C$ 731Free CancellationRating
7.0
3,001 reviews
Search Iberia 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$ 705. Generally, Virgin Atlantic has 5 flights on this route every week with an average price of C$ 1,001. Virgin Atlantic is rated 7.5/10 by our users.

  • Iberia Flights From Seattle to London

    C$ 731 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$ 867, however, with flight time and availability significantly affecting the price. Iberia (7.0/10 from 3,001 user reviews) flies into London from Seattle 2 times in an average week so prices can vary.

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Hounslow
Ipswich
Dartford
Gatwick
Ilford
Chelmsford
Wokingham
Slough
Canterbury
Feltham
Hayes
Uxbridge
Wembley
Waterlooville
Newport
Basingstoke
Milton Keynes
Dover
Worthing
Maidstone

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.

An easier way to manage your London trip

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Find better results for your trip to the United Kingdom

Fly into one of these airports located in London

Airports listed have a maximum distance of 57.3 km from London
London City Airport
London Gatwick Airport
London Heathrow Airport
London Luton Airport
London Southend Airport
London Stansted Airport