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Cheap flights from Seattle to London from C$ 389

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 1/11. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
17 Oct — 24 Oct1
1 adult
1 adult, Economy

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or August, booked 51 days in advance, depart on a Sunday or Thursday and return on a Monday

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 September 2025.

Round-trip from

C$ 699

One-way from

C$ 389

Popular in

June

Cheapest in

October

Average price

C$ 959

Good round-trip deal

C$ 924 or less

Good one-way deal

C$ 463 or less
Icelandair
  • Icelandair
  • 1/10-15/10
  • 2 total stops
  • 24h 40m total
  • Seattle to London
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1/11
  • 1/11
  • 2 total stops
  • 40h 42m total
  • Seattle to London
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Highest demand for flights based on searches. 15% potential increase in price (C$ 260 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 44 potential savings vs. average RT price).
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Average for round-trip flights in September 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

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 September 2025.

Wed 1/107:00 p.m.SEA - LGW
1 stop11h 40mIcelandair
Wed 15/103:40 p.m.LGW - SEA
1 stop13h 00mIcelandair
Deal found 16/9C$ 699
Mon 22/98:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Thu 2/106:15 a.m.LHR - SEA
1 stop19h 25mDelta
Deal found 15/9C$ 700
Wed 1/105:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Wed 15/106:15 a.m.LHR - SEA
1 stop19h 25mDelta
Deal found 16/9C$ 702
Wed 1/105:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Tue 14/106:30 a.m.LHR - SEA
1 stop17h 35mDelta
Deal found 15/9C$ 703
Sun 28/98:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Tue 14/106:30 a.m.LHR - SEA
1 stop13h 20mDelta
Deal found 16/9C$ 704
Sat 22/118:00 p.m.SEA - LHR
1 stop31h 50mUnited Airlines
Tue 2/1211:10 a.m.LHR - SEA
1 stop34h 10mUnited Airlines
Deal found 16/9C$ 706
Mon 22/97:15 a.m.SEA - LHR
1 stop18h 45mDelta
Wed 1/1011:30 a.m.LHR - SEA
1 stop14h 10mDelta
Deal found 15/9C$ 707
Mon 27/1012:41 p.m.SEA - LHR
2 stops37h 59mUnited Airlines
Fri 7/112:30 p.m.LHR - SEA
1 stop27h 01mUnited Airlines
Deal found 16/9C$ 710
Tue 23/95:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Tue 7/101:25 p.m.LHR - SEA
Nonstop10h 05mDelta
Deal found 15/9C$ 711
Mon 3/112:35 p.m.SEA - LGW
1 stop12h 20mIcelandair
Wed 19/1111:55 a.m.LGW - SEA
1 stop13h 05mIcelandair
Deal found 15/9C$ 713
Tue 21/101:30 p.m.SEA - LHR
1 stop12h 20mMultiple Airlines
Wed 29/1012:20 p.m.LHR - SEA
Nonstop10h 25mMultiple Airlines
Deal found 14/9C$ 713
Fri 3/103:45 p.m.SEA - LGW
1 stop14h 55mIcelandair
Mon 20/103:40 p.m.LGW - SEA
1 stop13h 00mIcelandair
Deal found 17/9C$ 714

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 17 September 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 - LHR

SEALHR

Seattle/Tacoma Intl

Wed 1/10

5:35 p.m.-11:20 a.m.

Nonstop9h 45m

London Heathrow

Wed 15/10

6:15 a.m.-5:40 p.m.

1 stop19h 25m

C$ 702

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 1/10

8:25 p.m.-2:15 p.m.

Nonstop9h 50m

London Heathrow

Wed 15/10

6:15 a.m.-11:15 a.m.

1 stop13h 00m

C$ 702

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 29/10

9:25 a.m.-7:05 a.m.

1 stop14h 40m

London Heathrow

Tue 11/11

6:20 a.m.-11:25 a.m.

1 stop13h 05m

C$ 708

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 9/3

7:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Thu 26/3

2:55 p.m.-5:55 p.m.

Nonstop10h 00m

C$ 711

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 3/3

1:25 p.m.-7:00 a.m.

Nonstop9h 35m

London Heathrow

Tue 31/3

9:25 a.m.-11:10 a.m.

Nonstop9h 45m

C$ 711

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 9/3

7:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Tue 31/3

9:25 a.m.-11:10 a.m.

Nonstop9h 45m

C$ 711

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 5/11

2:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Fri 21/11

11:55 a.m.-5:00 p.m.

1 stop13h 05m

C$ 713

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Fri 7/11

2:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Wed 19/11

11:55 a.m.-5:00 p.m.

1 stop13h 05m

C$ 713

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 15/10

8:25 p.m.-2:15 p.m.

Nonstop9h 50m

London Heathrow

Wed 22/10

5:25 p.m.-7:50 p.m.

Nonstop10h 25m

C$ 713

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Fri 7/11

2:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Fri 21/11

11:55 a.m.-5:00 p.m.

1 stop13h 05m

C$ 713

Flights are sorted by cheapest round-trip flights first.

Deals found on 16/9

Showing 1-10 of 43 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 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?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to London. Price data was last updated on 12 September 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 51 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$ 560). Flying from Seattle to London in July is currently the most expensive (average of C$ 856). 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 September 2025.

It’s optimal to fly from Seattle to London in the morning. By choosing this option you can save up to 28% on the cost of your flight, compared to a flight in the afternoon.

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 September 2025.

The most flights from SEA to LON are scheduled on a Monday (21 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (15 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 71% 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.

Reykjavik (KEF) is the most affordable 1-stop option, with an average round-trip price of C$ 697.

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 Munich (MUC) offer the fastest connection on this route, with an average layover time of 1h 25m.

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 September 2025.
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
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.
Air France
7.4
Good
1,468 reviews
Air France
7.4
Good
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.
Virgin Atlantic
7.4
Good
664 reviews
Air France
7.4
Good
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.
Icelandair
7.0
Good
545 reviews
Air France
7.4
Good
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.
Iberia
7.0
Good
2,925 reviews
Air France
7.4
Good
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.
British Airways
6.7
Okay
7,367 reviews
Air France
7.4
Good
1,468 reviews
Check prices

Entertainment

7.0

Overall

7.4

Boarding

7.4

Comfort

7.4

Crew

8.2

Food

7.0

Reviews

1 / 20
10.0
Excellent

SYLVIA,Apr 2025

TLV - CDG

A newer plane. The flight from TelAviv to Paris was on a new aircraft, wider seat. ,more privacy. Nice toilets. The flight from Paris to Santiago Chile was on a very old aircraft. Awful toilets, outmoded sits etc.

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 20 outbound flights to London per day from 4 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?

    Delta, Virgin Atlantic, and British Airways can get you from Seattle to London in just under 9h 30m. Your travel time will be generally consistent. The distance between Seattle and London is about 7697 km. All flights are typically direct.

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

    According to our current data, Icelandair (C$ 573), Virgin Atlantic (C$ 694), and British Airways (C$ 698) offers the cheapest pricing from Seattle to London. These flights start at 45% 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 Aeromexico (90%), KLM (83%) and Air France (83%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 349. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 777 on average, our data indicates C$ 736 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$ 560). Flying from Seattle to London in July is currently the most expensive (average of C$ 856). 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
Brentford
Sutton
Hounslow
Slough
Marlow
Milton Keynes
Romford
Watford
Bedford
Luton
Southall

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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 4 airlines flying from Seattle to London

Discover the top 4 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 17 September 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 573AverageC$ 759FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Virgin AtlanticCheapestC$ 694AverageC$ 980FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
British AirwaysCheapestC$ 698AverageC$ 1,126FlexibilityNo cancel feeOn-time70%
Search British Airways flights
IberiaCheapestC$ 720AverageC$ 854FlexibilityNo cancel feeOn-time77%
Search Iberia 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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