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Cheap flights from Seattle to London from C$ 507

SEA — LON
31 Oct — 7 Nov1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in January or April, booked 82 days in advance, depart on a Sunday or Saturday and return on a Tuesday

Cheap flight deals from Seattle to London

Enter your travel dates to find the best prices.

Cheapest flights from Seattle to London

Fri 4/1212:31 p.m. -
2 stops36h 49m
Mon 7/126:40 a.m. -
2 stops21h 44m
Deal found 29/9C$ 1,089
Fri 13/112:50 p.m. -
3 stops34h 05m
Sat 21/113:35 p.m. -
3 stops29h 25m
Deal found 29/9C$ 1,106
Sat 14/1111:17 p.m. -
1 stop14h 03m
Mon 16/1111:05 a.m. -
2 stops42h 44m
Deal found 30/9C$ 1,115
Sun 29/112:35 p.m. -
1 stop20h 55m
Mon 14/1212:15 p.m. -
1 stop12h 45m
Deal found 30/9C$ 1,119
Fri 27/112:35 p.m. -
1 stop20h 55m
Tue 22/1212:15 p.m. -
1 stop12h 45m
Deal found 25/9C$ 1,120
Fri 6/112:35 p.m. -
1 stop20h 55m
Tue 10/118:35 p.m. -
1 stop28h 25m
Deal found 30/9C$ 1,122
Mon 5/107:00 p.m. -
1 stop32h 55m
Mon 9/118:35 p.m. -
1 stop28h 25m
Deal found 27/9C$ 1,123
Sat 7/1111:10 p.m. -
2 stops35h 20m
Tue 10/115:00 p.m. -
2 stops37h 04m
Deal found 30/9C$ 1,132
Sun 13/122:35 p.m. -
1 stop20h 55m
Tue 22/1212:15 p.m. -
1 stop12h 45m
Deal found 27/9C$ 1,139
Fri 13/112:35 p.m. -
2 stops18h 20m
Sat 21/111:00 p.m. -
3 stops36h 00m
Deal found 29/9C$ 1,145
Tue 6/103:55 p.m. -
1 stop17h 45m
Sat 10/1010:20 a.m. -
1 stop35h 25m
Deal found 26/9C$ 1,150
Wed 28/1010:50 a.m. -
2 stops23h 00m
Fri 30/107:40 a.m. -
2 stops20h 16m
Deal found 28/9C$ 1,157

Find flight deals from Seattle to London

Round-trip from

C$ 1,069

One-way from

C$ 507

Popular in

June

Cheapest in

January

Average price

C$ 1,163

Good round-trip deal

C$ 1,145 or less

Good one-way deal

C$ 592 or less
United Airlines
  • United Airlines
  • 11/1-13/1
  • 2 total stops
  • 29h 25m total
  • Seattle to London
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Alaska Airlines
  • Alaska Airlines
  • 27/12-31/12
  • Nonstop
  • 9h 25m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (C$ 369 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 59 potential savings vs. average RT price).
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Average for round-trip flights in October 2026
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
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Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).
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Cheapflights Fare Finder

 
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

Cheapest round-trip

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sun 27/12

4:50 p.m.-10:40 a.m.

Nonstop9h 50m

London Heathrow

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 507

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 9/11

3:25 p.m.-3:45 p.m.

1 stop16h 20m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 538

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 2/11

3:25 p.m.-3:45 p.m.

1 stop16h 20m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 538

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 9/11

9:45 a.m.-3:45 p.m.

2 stops22h 00m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 545

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Thu 17/12

2:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 568

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Thu 12/11

10:56 p.m.-8:25 a.m.

2 stops25h 29m

London Heathrow

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 608

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Thu 29/10

5:05 p.m.-3:45 p.m.

1 stop15h 40m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 609

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Thu 12/11

4:05 p.m.-3:45 p.m.

1 stop15h 40m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 611

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Fri 13/11

3:25 p.m.-3:45 p.m.

1 stop16h 20m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 611

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Tue 3/11

4:05 p.m.-3:45 p.m.

1 stop15h 40m

London Gatwick

Wed 31/12

12:00 a.m.-3:00 p.m.

Nonstop0h 00m

C$ 645

Flights are sorted by cheapest round-trip flights first.

Deals found on 27/9

Showing 1-10 of 43 resultsSorted by cheapest first
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Best time to book a flight from Seattle to London

Have a flexible travel schedule? Discover the best time to fly to London from Seattle with our price prediction graph.
Estimated round-trip price

Cheapflights Insights

Everything you need to know about your flight from Seattle to London

What is the cheapest month to book a flight from Seattle to London?

Currently, January is the cheapest month in which you can book a flight from Seattle to London (average of C$ 963). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,724). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SEA to LON?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to London as you normally would.

Weekly flight availability from Seattle to London

The most flights from SEA to LON are scheduled on a Tuesday (25 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (20 on average).

How much does it cost to fly round-trip from Seattle to London?

Airfare is typical for this route at the moment.
Seattle to London flights typically cost between C$ 1,010 and C$ 1,407 in January.
The cheapest round-trip price found within the last 5 days was C$ 1,069 on United Airlines (11 Jan-13 Jan).

What’s the top layover airport for flights from Seattle to London?

Reykjavik (KEF) – chosen by Cheapflights users on 81% of one-stop itineraries from Seattle to London on Cheapflights.

What’s the cheapest layover airport for flights from Seattle to London?

Reykjavik (KEF) is the most affordable 1-stop option, with an average round-trip price of C$ 1,051.

What’s the fastest layover option from Seattle to London?

Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 11h 50m.

Which airport typically offers the quickest layover for flights from Seattle to London?

Flights via Dublin (DUB) offer the fastest connection on this route, with an average layover time of 1h 35m.

How often are flights from Seattle to London delayed?

About 14% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 130 minutes.

What is the most punctual flight time for Seattle to London flights?

Historically, flights departing at night are less likely to be delayed, whereas flights leaving in the evening tend to experience delays more often.

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

Saturday tends to have the lowest number of delays on this route, whereas Thursday has historically faced a higher average of delays compared to other days of the week.

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

Over the past year, Virgin Atlantic has had the lowest number of delays on this route, with just 5% of flights being delayed.

How far ahead should I book a flight from Seattle to London?

The price you pay for your flight from Seattle to London may vary depending on when you book. For the best chance of a lower fare, look to book 64 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Reviews of airlines servicing London

Get a feel of what it's like to fly with Alaska Airlines and Virgin Atlantic from Seattle to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
7.9
Good
13,002 reviews
Check prices

Comfort

7.8

Overall

7.9

Boarding

8.1

Entertainment

7.0

Food

7.0

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle
Alaska Airlines
7.9
Good
13,002 reviews
Alaska Airlines
7.9
Good
13,002 reviews
Check prices

Comfort

7.8

Overall

7.9

Boarding

8.1

Entertainment

7.0

Food

7.0

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle
Virgin Atlantic
7.4
Good
694 reviews
Alaska Airlines
7.9
Good
13,002 reviews
Check prices

Comfort

7.8

Overall

7.9

Boarding

8.1

Entertainment

7.0

Food

7.0

Crew

8.5

Reviews

1 / 20
6.0
Good

Anonymous,Jul 2026

SEA - LHR

Alaska has a brilliant crew. And the seats are good. As much as i loved my trip from Heathrow to Seattle, i definitely did not feel the same on the return flight. A lot was due to feeling very cramped and unfortunately for me, i had a kicker behind me and a passenger who did not stop moving (but constantly) next to me. The good was not good and i noticed that most people around me left most of their meal. The ice cream was very nice. I did not have breakfast. However the food was very nice on the way to Seattle

Related info for your journey

  • What airport do you fly from for flights from Seattle to London?

    Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to London. On average, Seattle/Tacoma Intl has 24 outbound flights to London per day from 1 airline. Seattle/Tacoma Intl is conveniently located just 18.4 km from Seattle’s city centre.

  • How long is the flight from Seattle to London?

    Scandinavian Airlines, Virgin Atlantic, and Delta can get you from Seattle to London in just under 17h 56m. Your travel time can differ by up to 15h 39m. The distance between Seattle and London is about 7697 km. This flight may include one or multiple stops.

  • What is the cheapest airline to fly from Seattle to London round-trip?

    According to our current data, Icelandair (C$ 716), offers the cheapest pricing from Seattle to London. This flight start at 42% lower than the current average price 3 months from now.

  • What are the most reliable airlines from Seattle to London?

    The top 3 most reliable airlines when flying from Seattle to London are Scandinavian Airlines (95%), KLM (94%) and SAUDIA (94%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 537. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 1,270 on average, our data indicates C$ 1,745 when flying from Seattle to London.

  • Can I find deals for flights from Seattle to London that include hotel bookings?

    Yes. In addition to deals on Seattle to London flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to London?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to London.

  • Can I find deals for business class flights from Seattle to London?

    Yes. Cheapflights offers flight deals from Seattle to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to London?

    Currently, January is the cheapest month in which you can book a flight from Seattle to London (average of C$ 963). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,724). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Gatwick
Romford
Twickenham
Ilford
Bromley
Sutton
Luton
Slough
Marlow
Cobham
Hounslow
Wembley
Watford
High Wycombe

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Seattle to London

Seattle to Heathrow flights
Seattle to Gatwick flights
Seattle to Manchester flights

Top airline flying from Seattle to London

AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 716AverageC$ 891FlexibilityNo cancel feeOn-time76%
Search Icelandair flights

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