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Cheap flights from London to Seattle from £397

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 21/8. Fares are subject to change and may not be available on all flights or dates of travel.
LON — SEA
16 Jul — 23 Jul1
1 adult

Cheapflights Tip: The best prices from London to Seattle/Tacoma Intl are usually found in January or March, booked 81 days in advance, depart on a Tuesday or Wednesday and return on a Tuesday

Cheap flight deals from London to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from London (LON) to Seattle (SEA). 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 11 July 2025.

Round-trip from

£474

One-way from

£397

Popular in

August

Cheapest in

January

Average price

£723

Good round-trip deal

£529 or less

Good one-way deal

£711 or less
SWISS
  • SWISS
  • 6/9-23/9
  • 4 total stops
  • 69h 02m total
  • London to Seattle
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21/8
  • 21/8
  • 2 total stops
  • 24h 50m total
  • London to Seattle
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Highest demand for flights based on searches. 15% potential increase in price (£73 potential increase over avg. return price).
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Cheapest flight prices on average. 2% potential price decrease (£12 potential savings vs. average return price).
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Average for round-trip flights in July 2025
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Price to beat on a round-trip flight from London (LON) to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from London (LON) to Seattle/Tacoma Intl.
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Find flight deals from London to Seattle

Cheapest flights from London to Seattle
Explore the most affordable flight options available from London to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 11 July 2025.

Sat 6/920:05LHR - SEA
2 stops30h 31mSWISS
Mon 22/914:29SEA - LHR
2 stops20h 51mSWISS
Deal found 9/7£474
Tue 25/1112:15LHR - SEA
1 stop12h 45mIcelandair
Mon 23/214:35SEA - LHR
1 stop12h 15mIcelandair
Deal found 10/7£475
Sat 6/918:40LGW - SEA
2 stops31h 56mSWISS
Tue 21/1013:00SEA - LGW
2 stops20h 50mSWISS
Deal found 10/7£476
Fri 12/906:30LHR - SEA
2 stops15h 46mMultiple Airlines
Sun 14/905:30SEA - LHR
2 stops17h 00mMultiple Airlines
Deal found 9/7£477
Mon 25/812:10LGW - SEA
1 stop17h 49mJetBlue
Tue 9/911:30SEA - LGW
1 stop14h 05mJetBlue
Deal found 9/7£478
Tue 5/815:40LGW - SEA
1 stop13h 00mIcelandair
Wed 3/915:45SEA - LGW
1 stop12h 00mIcelandair
Deal found 10/7£478
Tue 25/1119:25LHR - SEA
2 stops31h 27mAustrian Airlines
Mon 23/208:00SEA - LHR
1 stop18h 50mAustrian Airlines
Deal found 10/7£478
Wed 27/817:25LHR - SEA
Nonstop10h 20mVirgin Atlantic
Tue 9/920:25SEA - LHR
Nonstop9h 50mVirgin Atlantic
Deal found 9/7£480
Sat 6/906:30LHR - SEA
1 stop13h 25mLufthansa
Mon 22/914:00SEA - LHR
1 stop13h 45mLufthansa
Deal found 9/7£481
Sun 19/1006:30LHR - SEA
2 stops15h 46mUnited Airlines
Sun 2/1119:13SEA - LHR
2 stops18h 07mUnited Airlines
Deal found 10/7£485
Sat 6/909:20LCY - SEA
1 stop13h 30mSWISS
Mon 22/915:19SEA - LCY
2 stops19h 26mSWISS
Deal found 9/7£487
Wed 27/818:05LHR - SEA
2 stops51h 45mScandinavian Airlines
Mon 8/916:00SEA - LHR
1 stop17h 40mScandinavian Airlines
Deal found 10/7£488

Cheapflights Fare Finder

Customise your flight search to find flights from London to Seattle 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 11 July 2025.
Use the filters below to find and compare flights from London to Seattle that are best for you.

Fly from

London

Fly to

Seattle

Route

Depart

Return

Price

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sat 6/9

20:05-18:36

2 stops30h 31m

Seattle/Tacoma Intl

Mon 22/9

14:29-19:20

2 stops20h 51m

£474

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 25/11

12:15-17:00

1 stop12h 45m

Seattle/Tacoma Intl

Wed 25/2

14:35-19:30

1 stop20h 55m

£475

LondonSeattle

LGW - SEA

LGWSEA

London Gatwick

Sat 6/9

18:40-18:36

2 stops31h 56m

Seattle/Tacoma Intl

Tue 21/10

13:00-17:50

2 stops20h 50m

£476

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 12/9

06:30-14:16

2 stops15h 46m

Seattle/Tacoma Intl

Sun 14/9

05:30-06:30

2 stops17h 00m

£477

LondonSeattle

LGW - SEA

LGWSEA

London Gatwick

Mon 25/8

12:10-21:59

1 stop17h 49m

Seattle/Tacoma Intl

Tue 9/9

11:30-09:35

1 stop14h 05m

£478

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 25/11

19:25-18:52

2 stops31h 27m

Seattle/Tacoma Intl

Mon 23/2

08:00-10:50

1 stop18h 50m

£478

LondonSeattle

LGW - SEA

LGWSEA

London Gatwick

Tue 5/8

15:40-20:40

1 stop13h 00m

Seattle/Tacoma Intl

Wed 3/9

15:45-11:45

1 stop12h 00m

£478

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Wed 27/8

17:25-19:45

Nonstop10h 20m

Seattle/Tacoma Intl

Tue 9/9

20:25-14:15

Nonstop9h 50m

£480

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sat 6/9

06:30-11:55

1 stop13h 25m

Seattle/Tacoma Intl

Mon 22/9

14:00-11:45

1 stop13h 45m

£481

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sun 19/10

06:30-14:16

2 stops15h 46m

Seattle/Tacoma Intl

Sun 2/11

23:59-07:30

1 stop23h 31m

£485

Flights are sorted by cheapest return flights first.

Deals found on 10/7

Showing 1-10 of 39 results
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Best time to book a flight from London to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from London 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 London to Seattle

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

Use this chart to determine the optimal time to book a return flight from London to Seattle. Price data was last updated on 27 June 2025.

Booking 81 days in advance of your planned departure date is, on average, the best time to get cheap flights from London to Seattle. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, January is the cheapest month in which you can book a flight from London to Seattle (average of £622). Flying from London to Seattle in July is currently the most expensive (average of £946). 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 LON to SEA?

Find hourly flight availability from London to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 11 July 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 19% on flights from London to Seattle by exploring options for tickets in the evening.

What is the cheapest day to fly from London to Seattle?

Use this chart to determine the cheapest time to fly return from London to Seattle. Price data was last updated on 16 December 2024.

Travellers seeking maximum savings on their London to Seattle flight should consider departing on Monday evenings when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from London to Seattle

Explore weekly flight availability from London to Seattle. 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 11 July 2025.

The most flights from LON to SEA are scheduled on a Monday (22 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (11 on average).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated 11 July 2025.
Read reviews from past customers who have flown with Delta, KLM, andAustrian Airlines from London to Seattle. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.
Delta
8.0
Very Good
7,951 reviews
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.
KLM
7.8
Good
1,372 reviews
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.
Austrian Airlines
7.6
Good
811 reviews
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.
SWISS
7.5
Good
1,655 reviews
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.
United Airlines
7.4
Good
8,846 reviews
Delta
8.0
Very Good
7,951 reviews
Check prices

Entertainment

7.9

Comfort

7.9

Crew

8.5

Boarding

8.2

Overall

8.0

Food

7.3

Reviews

1 / 20
8.0
Excellent

Michael,Jul 2025

AMS - ATL

Overall it was great experience, with the exception of snack food. The food offered in two main meals was just fine but for the mid-flight snack, the only option was a large cookie, too sweet and high sugar content. Snacks at the back of the plane were also mainly sweets. There was one nice baked cheddar option but it quickly ran out.

Related info for your journey

Find useful and relevant information for your journey from London to Seattle. 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 into for flights to Seattle from London?

    Located just 11.4 mi from the city center, Seattle/Tacoma Intl is the airport most travelers will use when flying to Seattle from London. Booking flights from London to Seattle/Tacoma Intl (SEA) should be relatively easy as there are 18 daily inbound flights from London from 13 different airlines.

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

    SWISS, at £474, was found to be the cheapest airline from London to Seattle.Alternate airlines flying return to your destination include Icelandair and JetBlue. SWISS is priced at 14% lower than the current average price of a flight leaving 3 months from now.

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

    £397 is the cheapest one-way deal found within the past few days, from WestJet. You may also be able to find cheap deals on Aer Lingus and Icelandair, with prices starting from £404 and £435, respectively.

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

    When deciding which route to take from London to Seattle consider London Heathrow - Seattle/Tacoma Intl, London Gatwick - Seattle/Tacoma Intl or London City - Seattle/Tacoma Intl as they are the most popular.

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

    Consider Aeromexico (95%), KLM (93%) or Air France (93%) when booking your flight. These represent the most reliable airlines when flying from London to Seattle.

  • What are the cheapest flights from London to Seattle?

    On average you can expect to pay £2,160 for a flight from London to Seattle. The cheapest flight overall is £464 while the most popular route, (London Heathrow - Seattle/Tacoma Intl) is currently priced at £428.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from London to Seattle 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 London to Seattle?

    Currently, January is the cheapest month in which you can book a flight from London to Seattle (average of £622). Flying from London to Seattle in July is currently the most expensive (average of £946). 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
Tacoma
Leavenworth
Bothell
SeaTac

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Fly from London to Seattle on these airlines

Choose from the following airlines for your flight from London to Seattle. Flights are based on user searches made on Cheapflights and were last updated on 11 July 2025.
Virgin Atlantic flights from London to Seattle/Tacoma Intl
British Airways flights from London to Seattle/Tacoma Intl
Finnair flights from London to Seattle/Tacoma Intl

Top 10 airlines flying from London to Seattle

Discover the top 10 airlines that operate flights from London to Seattle. 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 11 July 2025.
AirlineCheapestAverageFlexibilityOn-time
Aer LingusCheapest£7Average£655FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
IcelandairCheapest£321Average£492FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Air FranceCheapest£381Average£562FlexibilityNo cancel feeOn-time77%
Search Air France flights
LufthansaCheapest£381Average£483FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
United AirlinesCheapest£394Average£503FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
FinnairCheapest£399Average£552FlexibilityNo cancel feeOn-time76%
Search Finnair flights
KLMCheapest£401Average£567FlexibilityNo cancel feeOn-time75%
Search KLM flights
British AirwaysCheapest£418Average£577FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£437Average£551FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
DeltaCheapest£439Average£614FlexibilityNo cancel feeOn-timeN/A
Search Delta 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 London to Seattle?

Cheapflights makes it easy to find London to Seattle flights by helping our users search from 900+ travel sites for deals. We also provide you with filters for cabin, price, airline, airports, number of stops, and many more to narrow down that perfect flight.

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

Millions of users choose and trust Cheapflights to book the best flight deals from London to Seattle for free. We help you search and compare prices from hundreds of airlines for the right flight just for you.

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

Certainly. Search results for flights to Seattle from London shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

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

Yes, Cheapflights offers price alerts on London to Seattle flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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