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Cheap flights from Seattle to London from £255

SEA — LON
13 Nov — 20 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 Wednesday or Monday and return on a Thursday

Cheap flight deals from Seattle to London

Enter your travel dates to find the best prices.

Cheapest flights from Seattle to London

Wed 25/1114:50 -
2 stops20h 35m
Wed 2/1220:15 -
2 stops26h 22m
Deal found 11/10£569
Tue 8/1214:35 -
1 stop12h 15m
Tue 15/1212:15 -
1 stop12h 45m
Deal found 9/10£569
Thu 12/1107:45 -
2 stops17h 50m
Wed 18/1120:15 -
1 stop23h 45m
Deal found 12/10£570
Wed 25/1114:50 -
3 stops34h 45m
Tue 1/1218:40 -
3 stops26h 20m
Deal found 12/10£570
Thu 12/1117:50 -
1 stop13h 10m
Mon 16/1110:25 -
1 stop13h 30m
Deal found 11/10£571
Sun 15/1114:35 -
1 stop12h 15m
Tue 1/1220:35 -
1 stop28h 25m
Deal found 12/10£571
Tue 17/1114:35 -
2 stops18h 20m
Tue 24/1119:30 -
3 stops29h 30m
Deal found 12/10£572
Wed 9/1214:35 -
1 stop12h 15m
Tue 15/1212:15 -
1 stop12h 45m
Deal found 9/10£573
Sun 29/1114:35 -
1 stop20h 55m
Sun 6/1220:35 -
1 stop28h 25m
Deal found 9/10£573
Fri 6/1114:50 -
2 stops20h 35m
Fri 13/1120:15 -
3 stops32h 44m
Deal found 9/10£575
Mon 23/1114:35 -
1 stop12h 15m
Tue 8/1212:15 -
1 stop12h 45m
Deal found 10/10£575
Sat 7/1110:51 -
2 stops21h 09m
Sun 8/1118:40 -
2 stops36h 15m
Deal found 12/10£576

Find flight deals from Seattle to London

Round-trip from

£569

One-way from

£255

Popular in

June

Cheapest in

January

Average price

£648

Good round-trip deal

£763 or less

Good one-way deal

£293 or less
25/11-2/12
  • 25/11-2/12
  • 4 total stops
  • 46h 57m total
  • Seattle to London
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8/12-31/12
  • 8/12-31/12
  • 2 total stops
  • 17h 45m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 16% potential increase in price (£100 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£17 potential savings vs. average return 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 return flight

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Tue 12/1

08:30-07:10

3 stops38h 40m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£264

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Mon 9/11

16:50-10:40

Nonstop9h 50m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£282

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sat 14/11

19:05-11:50

1 stop32h 45m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£282

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Fri 8/1

18:40-12:20

Nonstop9h 40m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£283

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sat 9/1

16:55-10:40

Nonstop9h 45m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£283

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 9/11

15:25-15:45

1 stop16h 20m

London Gatwick

Wed 31/12

00:00-15:00

Nonstop0h 00m

£286

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Tue 10/11

08:30-07:10

3 stops38h 40m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£289

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 4/1

14:35-13:00

2 stops14h 25m

London Gatwick

Wed 31/12

00:00-15:00

Nonstop0h 00m

£317
Fastest return journey

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Thu 12/11

18:45-12:10

Nonstop9h 25m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£320

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sat 14/11

16:50-10:40

Nonstop9h 50m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£320

Flights are sorted by cheapest return flights first.

Deals found on 12/10

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 return 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 £516). Flying from Seattle to London in June is currently the most expensive (average of £918). 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?

When flying from Seattle to London, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

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 Saturday, which is when the least amount of flights are scheduled (23 on average).

How much does it cost for a return flight from Seattle to London?

Airfare is typical for this route at the moment.
Seattle to London flights typically cost between £553 and £776 in November.
The cheapest return price found within the last 5 days was £569 on Multiple Airlines (25 Nov–2 Dec).

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

Reykjavik (KEF) – chosen by Cheapflights users on 50% of one-stop itineraries from Seattle to London on Cheapflights.

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

Reykjavik (KEF) is the most affordable one-stop option, with an average return flight price of £377.

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

Flights via Reykjavik (KEF) have the shortest average one-way travel time for one-stop routes: 12h 15m.

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

Flights via Reykjavik (KEF) offer the fastest connection on this route, with an average stopover time of 1h 25m.

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 have 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
13,064 reviews
Check prices

Food

7.0

Boarding

8.1

Overall

7.9

Crew

8.5

Entertainment

7.0

Comfort

7.8

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
13,064 reviews
Alaska Airlines
7.9
Good
13,064 reviews
Check prices

Food

7.0

Boarding

8.1

Overall

7.9

Crew

8.5

Entertainment

7.0

Comfort

7.8

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
7.5
Good
695 reviews
Alaska Airlines
7.9
Good
13,064 reviews
Check prices

Food

7.0

Boarding

8.1

Overall

7.9

Crew

8.5

Entertainment

7.0

Comfort

7.8

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?

    Seattle/Tacoma Intl (SEA) is the airport you will fly out of if you book a flight from Seattle to London. You should not have trouble finding flights to London from Seattle/Tacoma Intl; the airport handles an average of 24 outbound flights to London per day. You should also have plenty of airline options to choose from since 3 airlines have flights from the Seattle airport to London. It is only a 11.4 mi journey to Seattle/Tacoma Intl (SEA) from Seattle’s city center.

  • How long is the flight from Seattle to London?

    Airlines like Scandinavian Airlines, Delta, and Virgin Atlantic fly from Seattle to London in about 9h 50m. The time it takes to get you to your destination can typically vary by up to 12h 37m. The distance from Seattle to London is about 4783 mi. Both multi-stop and direct flights can be found to your destination and back.

  • What are the cheapest airlines flying from Seattle to London round-trip?

    Cheapflights users have booked flights from Seattle to London round-trip from £498. Other airlines that can offer you cheap pricing are British Airways, from £526, and Virgin Atlantic, from £585. Alaska Airlines is currently priced 25% below the average price you’ll pay for this route.

  • What are the cheapest airlines to fly from Seattle to London one-way?

    The cheapest airline one-way is Icelandair, with whom users have recently found tickets for as low as £129. However, be on the lookout for offers from Virgin Atlantic and British Airways, as they are both options that can get you from Seattle to London for a low price.

  • What are the most popular routes from Seattle to London?

    The most popular route from Seattle to London is Seattle/Tacoma Intl - London Heathrow. You may also consider Seattle/Tacoma Intl - London Gatwick or Seattle/Tacoma Intl - London Stansted.

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

    No one likes to see their flight delayed. When booking a flight from Seattle to London consider choosing KLM (93%), SAUDIA (93%) or Air France (93%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Seattle to London?

    The cheapest flight price from Seattle to London is £245. On average you can expect to pay £631. The most popular route, (Seattle/Tacoma Intl - London Heathrow), can usually be booked for £406.

  • 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 holiday 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 £516). Flying from Seattle to London in June is currently the most expensive (average of £918). 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

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Top 3 airlines flying from Seattle to London

AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapest£498Average£737FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
British AirwaysCheapest£526Average£691FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£585Average£693FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights

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Users can book flights with no change fees policies with our dedicated filters. Book flights from Seattle to London flexibly with Cheapflights today.

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