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Cheap flights from Seattle to London from £255

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 23/3. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
29 Dec — 5 Jan1
1 adult
1 adult, Economy, 0 bags

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or November, booked 9 days in advance, depart on a Tuesday or Thursday and return on a Wednesday

Cheap 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 29 November 2025.

Round-trip from

£442

One-way from

£255

Popular in

June

Cheapest in

October

Average price

£500

Good round-trip deal

£592 or less

Good one-way deal

£491 or less
Air Canada
  • Air Canada
  • 11/1-18/1
  • 3 total stops
  • 40h 16m total
  • Seattle to London
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British Airways
  • British Airways
  • 23/3
  • Nonstop
  • 9h 30m total
  • Seattle to London
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Highest demand for flights based on searches. 15% potential increase in price (£79 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£14 potential savings vs. average return price).
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Average for round-trip flights in November 2025
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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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Find 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 29 November 2025.

Wed 10/1211:34SEA - LHR
1 stop14h 26mAmerican Airlines
Thu 25/1214:55LHR - SEA
Nonstop10h 00mAmerican Airlines
Deal found 27/11£443
Wed 10/1207:35SEA - LHR
1 stop19h 50mDelta
Thu 25/1214:45LHR - SEA
Nonstop10h 05mDelta
Deal found 28/11£444
Tue 9/1210:05SEA - LHR
2 stops16h 05mMultiple Airlines
Tue 16/1207:25LHR - SEA
1 stop23h 03mMultiple Airlines
Deal found 26/11£444
Sun 7/1210:40SEA - LHR
1 stop13h 15mUnited Airlines
Tue 23/1215:20LHR - SEA
1 stop15h 48mUnited Airlines
Deal found 28/11£445
Sun 7/1210:05SEA - LHR
2 stops16h 05mMultiple Airlines
Tue 23/1213:35LHR - SEA
1 stop17h 12mMultiple Airlines
Deal found 28/11£446
Tue 9/1220:00SEA - LHR
1 stop31h 50mUnited Airlines
Tue 16/1207:25LHR - SEA
1 stop23h 03mUnited Airlines
Deal found 26/11£447
Mon 8/1216:48SEA - LHR
Nonstop9h 42mVirgin Atlantic
Mon 12/119:20LHR - SEA
1 stop24h 05mVirgin Atlantic
Deal found 29/11£447
Thu 4/1215:40SEA - LHR
1 stop12h 10mLufthansa
Thu 11/1214:30LHR - SEA
1 stop12h 46mLufthansa
Deal found 27/11£448
Tue 30/1213:35SEA - LHR
1 stop14h 25mUnited Airlines
Fri 9/112:05LHR - SEA
1 stop16h 52mUnited Airlines
Deal found 27/11£450
Sat 6/1223:55SEA - LHR
1 stop23h 10mDelta
Tue 16/1211:40LHR - SEA
1 stop15h 20mDelta
Deal found 28/11£451
Sun 7/1210:05SEA - LHR
2 stops16h 05mLufthansa
Tue 16/1210:25LHR - SEA
1 stop20h 03mLufthansa
Deal found 28/11£452
Wed 10/1205:50SEA - LHR
1 stop22h 00mUnited Airlines
Wed 17/1207:40LHR - SEA
1 stop36h 23mUnited Airlines
Deal found 28/11£453

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 29 November 2025.
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 - LTN

SEALTN

Seattle/Tacoma Intl

Wed 14/1

14:35-20:05

2 stops21h 30m

London Luton

Thu 22/1

06:15-17:00

2 stops18h 45m

£442

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 30/12

00:55-07:05

1 stop22h 10m

London Heathrow

Wed 14/1

12:20-14:49

Nonstop10h 29m

£443

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 12/1

18:25-11:55

Nonstop9h 30m

London Heathrow

Mon 19/1

06:30-11:50

1 stop13h 20m

£444

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 7/1

16:45-10:30

Nonstop9h 45m

London Heathrow

Fri 13/2

12:20-14:45

Nonstop10h 25m

£444

SeattleLondon

SEA - LTN

SEALTN

Seattle/Tacoma Intl

Sun 18/1

10:05-23:10

3 stops29h 05m

London Luton

Sun 25/1

14:30-12:10

2 stops29h 40m

£446

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 9/12

19:20-12:50

Nonstop9h 30m

London Heathrow

Tue 16/12

11:40-21:59

1 stop18h 19m

£447

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 12/1

10:05-11:50

1 stop17h 45m

London Heathrow

Mon 19/1

07:40-00:59

2 stops25h 19m

£451

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 4/4

19:02-12:20

1 stop33h 18m

London Heathrow

Tue 14/4

14:10-15:03

1 stop32h 53m

£452

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 26/4

20:25-14:15

Nonstop9h 50m

London Heathrow

Wed 6/5

08:40-15:50

1 stop15h 10m

£453

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 1/4

20:25-14:15

Nonstop9h 50m

London Heathrow

Thu 16/4

09:55-15:50

1 stop13h 55m

£453

Flights are sorted by cheapest return flights first.

Deals found on 27/11

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 28 November 2025.

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, May is the cheapest month in which you can book a flight from Seattle to London (average of £373). Flying from Seattle to London in June is currently the most expensive (average of £598). 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 29 November 2025.

One of the essential ways to save on airfare from Seattle to London is to remain as flexible as possible. Flights that are in the morning tend to be the most expensive. A flight in the afternoon could potentially save you up to 49% on airfare.

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 29 November 2025.

The most flights from SEA to LON are scheduled on a Friday (18 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (12 on average).

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

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 65% 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 £448.

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 Reykjavik (KEF) have the shortest average one-way travel time for one-stop routes: 11h 40m.

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 Reykjavik (KEF) offer the fastest connection on this route, with an average stopover time of 1h 28m.

How often are flights from Seattle to London delayed?

About 15% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 126 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 in the evening 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, La Costena have had the lowest number of delays on this route, with no flights being classified as 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 29 November 2025.
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
1,424 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Boarding

7.8

Overall

7.7

Crew

8.4

Food

7.2

Reviews

1 / 20
2.0
Mediocre

Abisola,Oct 2025

LOS - CDG

The food option was finished and what wa left was vegan pasta so I had to go without food for an 8 hour flight without any sort of empathy from crew that was mean.
KLM
7.7
Good
1,424 reviews
KLM
7.7
Good
1,424 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Boarding

7.8

Overall

7.7

Crew

8.4

Food

7.2

Reviews

1 / 20
2.0
Mediocre

Abisola,Oct 2025

LOS - CDG

The food option was finished and what wa left was vegan pasta so I had to go without food for an 8 hour flight without any sort of empathy from crew that was mean.
Virgin Atlantic
7.5
Good
675 reviews
KLM
7.7
Good
1,424 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Boarding

7.8

Overall

7.7

Crew

8.4

Food

7.2

Reviews

1 / 20
2.0
Mediocre

Abisola,Oct 2025

LOS - CDG

The food option was finished and what wa left was vegan pasta so I had to go without food for an 8 hour flight without any sort of empathy from crew that was mean.
Icelandair
7.0
Good
582 reviews
KLM
7.7
Good
1,424 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Boarding

7.8

Overall

7.7

Crew

8.4

Food

7.2

Reviews

1 / 20
2.0
Mediocre

Abisola,Oct 2025

LOS - CDG

The food option was finished and what wa left was vegan pasta so I had to go without food for an 8 hour flight without any sort of empathy from crew that was mean.
British Airways
6.7
Okay
7,545 reviews
KLM
7.7
Good
1,424 reviews
Check prices

Comfort

7.6

Entertainment

7.1

Boarding

7.8

Overall

7.7

Crew

8.4

Food

7.2

Reviews

1 / 20
2.0
Mediocre

Abisola,Oct 2025

LOS - CDG

The food option was finished and what wa left was vegan pasta so I had to go without food for an 8 hour flight without any sort of empathy from crew that was mean.

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 14 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 Delta, Virgin Atlantic, and United Airlines fly from Seattle to London in about 9h 30m. The time it takes to get you to your destination can typically vary by up to 12h 40m. 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 £358. Another airline that can offer you cheap pricing is Virgin Atlantic. British Airways is currently priced 37% 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 Lufthansa, with whom users have recently found tickets for as low as £283. However, be on the lookout for offers from Delta and United Airlines, 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 City.

  • 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 (86%), Delta (84%) or Virgin Atlantic (84%) 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 £346. On average you can expect to pay £853. The most popular route, (Seattle/Tacoma Intl - London Heathrow), can usually be booked for £358.

  • 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, May is the cheapest month in which you can book a flight from Seattle to London (average of £373). Flying from Seattle to London in June is currently the most expensive (average of £598). 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?

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Alternative routes for Seattle to London

See prices for flight routes from nearby airports that may be better suited for you.
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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 29 November 2025.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapest£358Average£529FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£373Average£595FlexibilityNo 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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