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Cheap flights from Seattle to London from C$ 509

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 22/8. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
17 Jun — 24 Jun1
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 51 days in advance, depart on a Wednesday or Saturday and return on a Monday

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 18 May 2026.

Sun 16/89:45 p.m.
SEA
-
LHR
Nonstop9h 50m
Multiple Airlines
Mon 31/89:25 p.m.
LHR
-
SEA
1 stop22h 20m
Multiple Airlines
Deal found 16/5C$ 1,236
Thu 1/1010:44 a.m.
SEA
-
LGW
2 stops24h 06m
Multiple Airlines
Fri 16/1010:20 a.m.
LGW
-
SEA
1 stop13h 40m
Multiple Airlines
Deal found 13/5C$ 1,237
Wed 19/89:45 p.m.
SEA
-
LHR
Nonstop9h 50m
KLM
Wed 2/96:30 a.m.
LHR
-
SEA
1 stop13h 17m
KLM
Deal found 18/5C$ 1,237
Tue 18/86:20 p.m.
SEA
-
LHR
Nonstop9h 50m
KLM
Thu 27/811:45 a.m.
LHR
-
SEA
1 stop12h 42m
KLM
Deal found 15/5C$ 1,240
Tue 18/86:20 p.m.
SEA
-
LHR
Nonstop9h 50m
Delta
Thu 27/811:45 a.m.
LHR
-
SEA
1 stop12h 42m
Delta
Deal found 14/5C$ 1,241
Tue 29/96:20 p.m.
SEA
-
LHR
Nonstop9h 50m
Delta
Fri 9/106:30 a.m.
LHR
-
SEA
1 stop13h 22m
Delta
Deal found 13/5C$ 1,243
Wed 19/88:20 p.m.
SEA
-
LHR
Nonstop9h 25m
British Airways
Wed 2/94:30 p.m.
LHR
-
SEA
Nonstop9h 55m
British Airways
Deal found 14/5C$ 1,244
Sat 12/99:55 p.m.
SEA
-
LHR
1 stop24h 25m
Delta
Thu 17/96:30 a.m.
LHR
-
SEA
1 stop13h 17m
Delta
Deal found 17/5C$ 1,245
Wed 12/811:21 a.m.
SEA
-
LHR
1 stop14h 39m
Delta
Thu 20/86:30 a.m.
LHR
-
SEA
1 stop13h 07m
Delta
Deal found 14/5C$ 1,247
Wed 19/83:54 p.m.
SEA
-
LHR
1 stop12h 41m
United Airlines
Wed 26/810:50 a.m.
LHR
-
SEA
1 stop14h 09m
United Airlines
Deal found 14/5C$ 1,248
Tue 1/99:50 p.m.
SEA
-
LHR
Nonstop9h 45m
Multiple Airlines
Thu 1/106:15 a.m.
LHR
-
SEA
1 stop13h 00m
Multiple Airlines
Deal found 18/5C$ 1,249
Sat 8/811:42 a.m.
SEA
-
LGW
2 stops23h 03m
Multiple Airlines
Sat 5/910:20 a.m.
LGW
-
SEA
1 stop13h 40m
Multiple Airlines
Deal found 15/5C$ 1,251

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 18 May 2026.

Round-trip from

C$ 1,236

One-way from

C$ 509

Popular in

June

Cheapest in

January

Average price

C$ 1,245

Good round-trip deal

C$ 1,297 or less

Good one-way deal

C$ 850 or less
Icelandair
  • Icelandair
  • 16/8-31/8
  • 1 total stop
  • 32h 10m total
  • Seattle to London
Search Deals
Delta
  • Delta
  • 22/8
  • 1 total stop
  • 23h 40m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 20% potential increase in price (C$ 377 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (C$ 59 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 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

 
Customize 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 629,999 searches. Data last updated 18 May 2026.
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 round-trip

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 19/8

9:45 p.m.-3:35 p.m.

Nonstop9h 50m

London Heathrow

Wed 2/9

6:30 a.m.-11:47 a.m.

1 stop13h 17m

C$ 1,237

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 29/7

9:50 p.m.-3:35 p.m.

Nonstop9h 45m

London Heathrow

Wed 2/9

6:30 a.m.-11:47 a.m.

1 stop13h 17m

C$ 1,240

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 1/9

6:20 p.m.-12:10 p.m.

Nonstop9h 50m

London Heathrow

Tue 8/9

6:15 a.m.-5:43 p.m.

1 stop19h 28m

C$ 1,251

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 29/7

7:00 a.m.-7:15 a.m.

2 stops16h 15m

London Heathrow

Wed 2/9

6:55 a.m.-4:59 p.m.

1 stop18h 04m

C$ 1,254

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 29/7

7:29 a.m.-9:25 a.m.

2 stops17h 56m

London Gatwick

Wed 2/9

10:25 a.m.-5:43 p.m.

1 stop15h 18m

C$ 1,263

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 2/6

3:55 p.m.-4:00 p.m.

1 stop16h 05m

London Heathrow

Tue 16/6

6:40 a.m.-1:45 p.m.

1 stop15h 05m

C$ 1,266
Quickest round-trip

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 4/8

9:45 p.m.-3:35 p.m.

Nonstop9h 50m

London Heathrow

Tue 25/8

5:45 p.m.-8:03 p.m.

Nonstop10h 18m

C$ 1,277

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 4/8

7:00 a.m.-8:25 a.m.

2 stops17h 25m

London Gatwick

Tue 25/8

9:25 a.m.-6:32 p.m.

2 stops17h 07m

C$ 1,293

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Mon 17/8

6:10 p.m.-6:50 p.m.

1 stop16h 40m

London Gatwick

Sun 21/2

3:35 p.m.-3:35 p.m.

1 stop32h 00m

C$ 1,303

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 30/8

6:20 p.m.-12:10 p.m.

Nonstop9h 50m

London Heathrow

Sat 5/9

6:30 a.m.-11:47 a.m.

1 stop13h 17m

C$ 1,399

Flights are sorted by cheapest round-trip flights first.

Deals found on 17/5

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 round-trip 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?

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 82 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, January is the cheapest month in which you can book a flight from Seattle to London (average of C$ 440). Flying from Seattle to London in November is currently the most expensive (average of C$ 3,385). 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 18 May 2026.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to London as you normally would.

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 18 May 2026.

The most flights from SEA to LON are scheduled on a Tuesday (22 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (18 on average).

How much does it cost to fly round-trip from Seattle to London?

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

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

Reykjavik (KEF) – chosen by Cheapflights users on 74% of one-stop itineraries from Seattle to London on Cheapflights.

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

Average round-trip fare for 1-stop flights from Seattle to London, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Dublin (DUB) is the most affordable 1-stop option, with an average round-trip price of C$ 739.

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

Shortest average travel time for 1-stop one-way flights from Seattle to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 11h 30m.

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

Average layover duration for 1-stop one-way flights from Seattle to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Salt Lake City (SLC) offer the fastest connection on this route, with an average layover time of 1h 53m.

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 128 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?

Tuesday tends to have the lowest number of delays on this route, whereas Wednesday 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 has 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 18 May 2026.
Get a feel of what it's like to fly with Air France,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.
Air France
7.4
Good
1,588 reviews
Check prices

Overall

7.4

Crew

8.2

Comfort

7.4

Boarding

7.5

Entertainment

7.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Grace,Apr 2026

JFK - CDG

Leg room was a bit tight and I had a hard time recovering a lost item but otherwise, great flight.
Air France
7.4
Good
1,588 reviews
Air France
7.4
Good
1,588 reviews
Check prices

Overall

7.4

Crew

8.2

Comfort

7.4

Boarding

7.5

Entertainment

7.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Grace,Apr 2026

JFK - CDG

Leg room was a bit tight and I had a hard time recovering a lost item but otherwise, great flight.
Virgin Atlantic
7.4
Good
688 reviews
Air France
7.4
Good
1,588 reviews
Check prices

Overall

7.4

Crew

8.2

Comfort

7.4

Boarding

7.5

Entertainment

7.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Grace,Apr 2026

JFK - CDG

Leg room was a bit tight and I had a hard time recovering a lost item but otherwise, great flight.
Icelandair
7.0
Good
656 reviews
Air France
7.4
Good
1,588 reviews
Check prices

Overall

7.4

Crew

8.2

Comfort

7.4

Boarding

7.5

Entertainment

7.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Grace,Apr 2026

JFK - CDG

Leg room was a bit tight and I had a hard time recovering a lost item but otherwise, great flight.
British Airways
6.7
Okay
7,988 reviews
Air France
7.4
Good
1,588 reviews
Check prices

Overall

7.4

Crew

8.2

Comfort

7.4

Boarding

7.5

Entertainment

7.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Grace,Apr 2026

JFK - CDG

Leg room was a bit tight and I had a hard time recovering a lost item but otherwise, great flight.

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?

    Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to London. On average, Seattle/Tacoma Intl has 21 outbound flights to London per day from 3 airlines. Seattle/Tacoma Intl is conveniently located just 18.4 km from Seattle’s city centre.

  • How long is the flight from Seattle to London?

    KLM, Virgin Atlantic, and SWISS can get you from Seattle to London in just under 9h 50m. Your travel time can differ by up to 7h 35m. The distance between Seattle and London is about 7697 km. This flight may include one or multiple stops.

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

    According to our current data, Virgin Atlantic (C$ 627), Icelandair (C$ 649), and British Airways (C$ 698) offers the cheapest pricing from Seattle to London. These flights start at 41% lower than the current average price 3 months from now.

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

    The top 3 most reliable airlines when flying from Seattle to London are KLM (96%), Air France (96%) and Delta (95%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 595. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 1,111 on average, our data indicates C$ 2,020 when flying from Seattle to London.

  • 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 vacation 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 C$ 440). Flying from Seattle to London in November is currently the most expensive (average of C$ 3,385). 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
Gatwick
Romford
Twickenham
Ilford
Bromley
Sutton
Slough
Marlow
Cobham
Watford
Luton
High Wycombe
Hounslow

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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.
Seattle to Heathrow flights
Seattle to Gatwick flights
Seattle to Manchester flights

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 629,999 searches. Data last updated 18 May 2026.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapestC$ 615AverageC$ 912FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapestC$ 627AverageC$ 995FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
IcelandairCheapestC$ 649AverageC$ 718FlexibilityNo cancel feeOn-time76%
Search Icelandair flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers 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?

Cheapflights helps you search for flights from Seattle to London via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

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

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from Seattle to London for you. Better yet — we are completely free to use.

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! Start tracking prices for Seattle to London flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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