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Cheap flights from Seattle to London from £275

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 21/3. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
14 Mar — 21 Mar1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in January or October, booked 9 days in advance, depart on a Tuesday or Thursday and return on a Wednesday

Cheap flight deals from Seattle to London

Enter your travel dates to find the best prices.

Cheapest flights from Seattle to London
Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 12 February 2026.

Fri 24/419:00
SEA
-
LHR
1 stop17h 20m
Icelandair
Mon 4/521:25
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 11/2£397
Mon 13/419:00
SEA
-
LGW
1 stop11h 40m
Icelandair
Sat 25/415:40
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 10/2£398
Mon 13/415:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Tue 21/413:05
LHR
-
SEA
1 stop15h 35m
Icelandair
Deal found 11/2£398
Mon 13/419:00
SEA
-
LGW
1 stop11h 40m
Icelandair
Wed 22/415:40
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 10/2£398
Mon 13/415:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 22/413:05
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 10/2£398
Fri 27/214:35
SEA
-
LGW
1 stop12h 20m
Icelandair
Fri 6/311:55
LGW
-
SEA
1 stop13h 05m
Icelandair
Deal found 11/2£399
Mon 9/315:35
SEA
-
STN
2 stops20h 15m
Multiple Airlines
Sun 15/318:00
STN
-
SEA
2 stops31h 00m
Multiple Airlines
Deal found 9/2£400
Sun 4/1015:40
SEA
-
LGW
1 stop15h 00m
Icelandair
Mon 12/1015:40
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 12/2£400
Mon 13/415:40
SEA
-
LHR
1 stop20h 40m
Icelandair
Sat 25/421:25
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 8/2£400
Mon 6/419:00
SEA
-
LHR
1 stop32h 55m
Icelandair
Wed 29/421:25
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 9/2£400
Wed 15/419:00
SEA
-
LGW
1 stop11h 40m
Icelandair
Thu 30/415:40
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 9/2£401
Tue 14/415:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Tue 28/413:05
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 9/2£401

Find flight deals from Seattle to London

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to London (LON). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 12 February 2026.

Round-trip from

£397

One-way from

£275

Popular in

June

Cheapest in

January

Average price

£501

Good round-trip deal

£452 or less

Good one-way deal

£302 or less
Icelandair
  • Icelandair
  • 24/4-4/5
  • 2 total stops
  • 45h 50m total
  • Seattle to London
Search Deals
21/3
  • 21/3
  • 3 total stops
  • 46h 45m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (£71 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£12 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 2026
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).
Search Deals

Cheapflights Fare Finder

 
Customise 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, Cheapflights users made 858,174 searches. Data last updated 12 February 2026.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Seattle

Fly to

London

Route

Depart

Return

Price

SeattleLondon

SEA - STN

SEASTN

Seattle/Tacoma Intl

Mon 9/3

15:35-18:50

2 stops20h 15m

London Stansted

Sun 15/3

18:00-18:00

2 stops31h 00m

£400

SeattleLondon

SEA - LTN

SEALTN

Seattle/Tacoma Intl

Mon 20/4

05:40-14:20

3 stops24h 40m

London Luton

Tue 28/4

05:40-22:50

3 stops25h 10m

£407

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 7/4

19:00-14:40

1 stop11h 40m

London Gatwick

Tue 14/4

15:40-20:40

1 stop13h 00m

£417

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 7/4

19:00-14:40

1 stop11h 40m

London Gatwick

Wed 15/4

15:40-20:40

1 stop13h 00m

£417

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Thu 16/4

19:00-14:40

1 stop11h 40m

London Gatwick

Thu 23/4

15:40-20:40

1 stop13h 00m

£418

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Thu 16/4

19:00-14:40

1 stop11h 40m

London Gatwick

Mon 27/4

15:40-20:40

1 stop13h 00m

£418

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Sat 18/4

19:00-14:40

1 stop11h 40m

London Gatwick

Fri 24/4

15:40-20:40

1 stop13h 00m

£418

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 10/3

17:40-10:30

Nonstop9h 50m

London Heathrow

Mon 16/3

10:00-12:35

1 stop33h 35m

£453

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 9/3

23:59-20:35

1 stop13h 36m

London Heathrow

Fri 20/3

06:35-14:20

1 stop14h 45m

£455

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 12/3

17:55-16:50

1 stop15h 55m

London Heathrow

Thu 19/3

06:30-12:35

1 stop13h 05m

£456

Flights are sorted by cheapest return flights first.

Deals found on 10/2

Showing 1-10 of 60 results
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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
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

Use this chart to determine the optimal time to book a return flight from Seattle to London. Price data was last updated on 6 February 2026.

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 9 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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

Currently, February is the cheapest month in which you can book a flight from Seattle to London (average of £362). Flying from Seattle to London in June is currently the most expensive (average of £564). 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?

Find hourly flight availability from Seattle to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 12 February 2026.

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

Explore weekly flight availability from Seattle to London. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 12 February 2026.

The most flights from SEA to LON are scheduled on a Monday (15 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (12 on average).

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

Share of one-stop return flights from Seattle to London chosen by Cheapflights users in the past 12 months, using the same stopover each way.

Reykjavik (KEF) – chosen by Cheapflights users on 61% of one-stop itineraries from Seattle to London on Cheapflights.

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

Average return fare for one-stop flights from Seattle to London, chosen by Cheapflights users in the past 12 months, with the same stopover each way.

Dublin (DUB) is the most affordable one-stop option, with an average return flight price of £434.

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

Shortest average travel time for one-stop one-way flights from Seattle to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by stopover airport.

Flights via Dublin (DUB) have the shortest average one-way travel time for one-stop routes: 11h 55m.

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

Average stopover duration for one-stop one-way flights from Seattle to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Dublin (DUB) offer the fastest connection on this route, with an average stopover time of 1h 49m.

How often are flights from Seattle to London delayed?

About 16% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 123 minutes.

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

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

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

Tuesday tends to have the lowest number of delays on this route, whereas Sunday 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 6% of flights being delayed.

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated 12 February 2026.
Get a feel of what it's like to fly with KLM, Virgin Atlantic, andIcelandair 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.
KLM
7.7
Good
1,452 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Food

7.3

Overall

7.7

Crew

8.4

Boarding

7.8

Reviews

1 / 20
10.0
Excellent

Snapyou,Jan 2026

TPA - LHR

Flight operated by Virgin Atlantic - usual high standard service by Virgin.
KLM
7.7
Good
1,452 reviews
KLM
7.7
Good
1,452 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Food

7.3

Overall

7.7

Crew

8.4

Boarding

7.8

Reviews

1 / 20
10.0
Excellent

Snapyou,Jan 2026

TPA - LHR

Flight operated by Virgin Atlantic - usual high standard service by Virgin.
Virgin Atlantic
7.5
Good
678 reviews
KLM
7.7
Good
1,452 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Food

7.3

Overall

7.7

Crew

8.4

Boarding

7.8

Reviews

1 / 20
10.0
Excellent

Snapyou,Jan 2026

TPA - LHR

Flight operated by Virgin Atlantic - usual high standard service by Virgin.
Icelandair
7.1
Good
614 reviews
KLM
7.7
Good
1,452 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Food

7.3

Overall

7.7

Crew

8.4

Boarding

7.8

Reviews

1 / 20
10.0
Excellent

Snapyou,Jan 2026

TPA - LHR

Flight operated by Virgin Atlantic - usual high standard service by Virgin.
British Airways
6.7
Okay
7,737 reviews
KLM
7.7
Good
1,452 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Food

7.3

Overall

7.7

Crew

8.4

Boarding

7.8

Reviews

1 / 20
10.0
Excellent

Snapyou,Jan 2026

TPA - LHR

Flight operated by Virgin Atlantic - usual high standard service by Virgin.

Related info for your journey

Find useful and relevant information for your journey from Seattle to London. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • 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 13 outbound flights to London per day. You should also have plenty of airline options to choose from since 2 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 Icelandair, United Airlines, and Delta fly from Seattle to London in about 11h 40m. The time it takes to get you to your destination can typically vary by up to 1h 56m. The distance from Seattle to London is about 4807 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 £347. Another airline that can offer you cheap pricing is Virgin Atlantic. British Airways is currently priced 36% 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 £158. However, be on the lookout for offers from British Airways and Virgin Atlantic, 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 American Airlines (78%), Alaska Airlines (78%) or Aer Lingus (78%) 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 £174. On average you can expect to pay £445. The most popular route, (Seattle/Tacoma Intl - London Heathrow), can usually be booked for £387.

  • 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, February is the cheapest month in which you can book a flight from Seattle to London (average of £362). Flying from Seattle to London in June is currently the most expensive (average of £564). 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
Milton Keynes
Croydon
Luton
Wembley
Gatwick
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Hounslow
Ilford
Hayes
Brentford
Colchester
Watford
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Chelmsford
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Crawley
Kingston upon Thames
Ipswich
Bedford
Romford

Browse thousands of different options on Cheapflights for your next trip

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Top 2 airlines flying from Seattle to London

Discover the top 2 airlines that operate flights from Seattle to London. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 12 February 2026.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapest£347Average£510FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£362Average£576FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Seattle to London?

Deals for Seattle to London flights are sourced from 900+ travel sites when you use Cheapflights. When all flight results come back, Cheapflights lets you sort and filter flights using different criteria to choose better, like price, airport, cabin class, and plenty of other options.

Why should you use Cheapflights to find cheap flight tickets from Seattle to London?

Cheapflights simply makes it quick and affordable to book flights from Seattle to London by bringing together all flight options from hundreds of airlines and agencies online — and put it in one place for you to choose from. Plus, Cheapflights is 100% free to use for all.

Can Cheapflights find flights from Seattle to London with no change fees?

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

Can Cheapflights notify me if prices for flights from Seattle to London become cheaper?

Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!

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