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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 13/4. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
16 Nov — 23 Nov1
1 adult
1 adult, Economy

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or August, 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 17 October 2025.

Round-trip from

£384

One-way from

£255

Popular in

June

Cheapest in

October

Average price

£494

Good round-trip deal

£497 or less

Good one-way deal

£354 or less
Icelandair
  • Icelandair
  • 18/11-23/11
  • 2 total stops
  • 25h 25m total
  • Seattle to London
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WestJet
  • WestJet
  • 13/4
  • 2 total stops
  • 16h 10m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (£75 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£13 potential savings vs. average return price).
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Average for round-trip flights in October 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 17 October 2025.

Tue 18/1114:35SEA - LGW
1 stop12h 20mIcelandair
Sun 23/1111:55LGW - SEA
1 stop13h 05mIcelandair
Deal found 16/10£384
Wed 12/1114:35SEA - STN
2 stops14h 45mMultiple Airlines
Wed 19/1106:30STN - SEA
2 stops18h 30mMultiple Airlines
Deal found 15/10£385
Sat 15/1114:35SEA - LGW
1 stop12h 20mIcelandair
Fri 21/1111:55LGW - SEA
1 stop13h 05mIcelandair
Deal found 14/10£385
Wed 12/1114:35SEA - LGW
1 stop12h 20mIcelandair
Wed 19/1111:55LGW - SEA
1 stop13h 05mIcelandair
Deal found 15/10£386
Mon 1/1214:35SEA - LHR
1 stop12h 15mIcelandair
Mon 8/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 17/10£386
Sat 6/1214:35SEA - LHR
1 stop12h 15mIcelandair
Fri 12/1212:15LHR - SEA
1 stop12h 45mIcelandair
Deal found 15/10£386
Tue 18/1114:35SEA - LHR
1 stop12h 15mIcelandair
Tue 25/1112:15LHR - SEA
1 stop12h 45mIcelandair
Deal found 15/10£387
Sat 15/1114:35SEA - LHR
1 stop12h 15mIcelandair
Sun 23/1112:15LHR - SEA
1 stop12h 45mIcelandair
Deal found 14/10£388
Sat 15/1114:35SEA - LHR
1 stop20h 55mIcelandair
Mon 24/1120:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 14/10£389
Tue 18/1114:35SEA - LHR
1 stop20h 55mIcelandair
Sun 7/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 15/10£389
Mon 24/1114:35SEA - LGW
1 stop12h 20mIcelandair
Sat 6/1211:55LGW - SEA
1 stop13h 05mIcelandair
Deal found 15/10£390
Wed 12/1114:35SEA - LTN
2 stops24h 30mMultiple Airlines
Wed 19/1106:50LTN - SEA
2 stops18h 10mMultiple Airlines
Deal found 15/10£391

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 17 October 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 - LGW

SEALGW

Seattle/Tacoma Intl

Mon 3/11

14:35-10:55

1 stop12h 20m

London Gatwick

Thu 13/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 18/11

14:35-10:55

1 stop12h 20m

London Gatwick

Sun 23/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 18/11

14:35-10:55

1 stop12h 20m

London Gatwick

Thu 27/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 18/11

14:35-10:55

1 stop12h 20m

London Gatwick

Tue 25/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 19/11

14:35-10:55

1 stop12h 20m

London Gatwick

Sun 23/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 4/11

14:35-10:55

1 stop12h 20m

London Gatwick

Thu 20/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Sun 16/11

14:35-10:55

1 stop12h 20m

London Gatwick

Sun 23/11

11:55-17:00

1 stop13h 05m

£384

SeattleLondon

SEA - STN

SEASTN

Seattle/Tacoma Intl

Wed 12/11

14:35-13:20

2 stops14h 45m

London Stansted

Wed 19/11

06:30-17:00

2 stops18h 30m

£385

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Sat 15/11

14:35-10:55

1 stop12h 20m

London Gatwick

Sun 23/11

11:55-17:00

1 stop13h 05m

£385

SeattleLondon

SEA - LTN

SEALTN

Seattle/Tacoma Intl

Wed 12/11

14:35-23:05

2 stops24h 30m

London Luton

Wed 19/11

06:50-17:00

2 stops18h 10m

£396

Flights are sorted by cheapest return flights first.

Deals found on 16/10

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 10 October 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, April is the cheapest month in which you can book a flight from Seattle to London (average of £361). Flying from Seattle to London in June is currently the most expensive (average of £590). 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 17 October 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 17 October 2025.

The most flights from SEA to LON are scheduled on a Wednesday (21 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (10 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 59% 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.

Reykjavik (KEF) is the most affordable one-stop option, with an average return flight price of £444.

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.

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 17 October 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
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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
1,404 reviews
KLM
7.7
Good
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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
670 reviews
KLM
7.7
Good
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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
556 reviews
KLM
7.7
Good
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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.
Iberia
7.0
Good
2,995 reviews
KLM
7.7
Good
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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
7,459 reviews
KLM
7.7
Good
1,404 reviews
Check prices

Boarding

7.8

Entertainment

7.1

Crew

8.4

Food

7.3

Comfort

7.6

Overall

7.7

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 16 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 Icelandair, Delta, and Virgin Atlantic fly from Seattle to London in about 9h 42m. The time it takes to get you to your destination can typically vary by up to 7h 48m. 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 £349. Other airlines that can offer you cheap pricing are British Airways, from £353, and Virgin Atlantic, from £368. Aer Lingus is currently priced 38% 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 WestJet, with whom users have recently found tickets for as low as £276. However, be on the lookout for offers from Virgin Atlantic 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%), Air France (86%) or Delta (86%) 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 £290. On average you can expect to pay £455. The most popular route, (Seattle/Tacoma Intl - London Heathrow), can usually be booked for £355.

  • 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, April is the cheapest month in which you can book a flight from Seattle to London (average of £361). Flying from Seattle to London in June is currently the most expensive (average of £590). 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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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 3 airlines flying from Seattle to London

Discover the top 3 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 17 October 2025.
AirlineCheapestAverageFlexibilityOn-time
Aer LingusCheapest£349Average£511FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
British AirwaysCheapest£353Average£593FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£368Average£609FlexibilityNo 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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