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Cheap flights from Seattle to London from C$ 520

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 18/3. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
5 Mar — 12 Mar1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or January, booked 64 days in advance, depart on a Sunday 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 3 February 2026.

Wed 25/22:35 p.m.
SEA
-
LGW
1 stop12h 20m
Icelandair
Mon 16/311:55 a.m.
LGW
-
SEA
1 stop13h 05m
Icelandair
Deal found 2/2C$ 746
Wed 7/103:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 21/109:25 p.m.
LHR
-
SEA
1 stop31h 15m
Icelandair
Deal found 1/2C$ 750
Sun 26/43:40 p.m.
SEA
-
LHR
1 stop20h 40m
Icelandair
Mon 4/59:25 p.m.
LHR
-
SEA
1 stop31h 15m
Icelandair
Deal found 2/2C$ 751
Wed 7/107:00 p.m.
SEA
-
LGW
1 stop11h 40m
Icelandair
Wed 21/103:40 p.m.
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 1/2C$ 769
Sun 12/47:00 p.m.
SEA
-
LGW
1 stop11h 40m
Icelandair
Wed 22/43:40 p.m.
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 3/2C$ 777
Sat 3/103:40 p.m.
SEA
-
LGW
1 stop15h 00m
Icelandair
Wed 7/103:40 p.m.
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 1/2C$ 781
Thu 1/103:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 7/101:05 p.m.
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 1/2C$ 787
Sun 26/47:00 p.m.
SEA
-
LGW
1 stop11h 40m
Icelandair
Wed 6/53:40 p.m.
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 3/2C$ 788
Thu 1/103:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Mon 5/109:25 p.m.
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 1/2C$ 788
Fri 18/93:40 p.m.
SEA
-
LGW
1 stop15h 00m
Icelandair
Mon 5/103:40 p.m.
LGW
-
SEA
1 stop13h 00m
Icelandair
Deal found 1/2C$ 791
Mon 21/93:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 7/101:05 p.m.
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 1/2C$ 796
Sat 2/57:00 p.m.
SEA
-
LGW
1 stop11h 40m
Icelandair
Tue 12/51:00 p.m.
LGW
-
SEA
1 stop12h 55m
Icelandair
Deal found 3/2C$ 799

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 3 February 2026.

Round-trip from

C$ 746

One-way from

C$ 520

Popular in

June

Cheapest in

October

Average price

C$ 897

Good round-trip deal

C$ 998 or less

Good one-way deal

C$ 444 or less
Icelandair
  • Icelandair
  • 25/2-16/3
  • 2 total stops
  • 25h 25m total
  • Seattle to London
Search Deals
Lufthansa
  • Lufthansa
  • 18/3
  • 1 total stop
  • 20h 25m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (C$ 260 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (C$ 46 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 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 3 February 2026.
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

Thu 16/4

7:00 p.m.-2:40 p.m.

1 stop11h 40m

London Gatwick

Mon 27/4

3:40 p.m.-8:40 p.m.

1 stop13h 00m

C$ 777

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 23/3

5:40 p.m.-10:30 a.m.

Nonstop9h 50m

London Heathrow

Tue 31/3

6:30 a.m.-11:45 a.m.

1 stop13h 15m

C$ 843

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 16/3

5:40 p.m.-10:30 a.m.

Nonstop9h 50m

London Heathrow

Tue 31/3

6:30 a.m.-11:45 a.m.

1 stop13h 15m

C$ 844

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 7/3

6:25 p.m.-11:55 a.m.

Nonstop9h 30m

London Heathrow

Thu 19/3

6:30 a.m.-12:35 p.m.

1 stop13h 05m

C$ 848

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 5/4

3:40 p.m.-1:20 p.m.

1 stop13h 40m

London Heathrow

Fri 24/4

7:25 a.m.-4:59 p.m.

1 stop17h 34m

C$ 870

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 20/3

10:25 p.m.-6:50 a.m.

1 stop25h 25m

London Heathrow

Mon 6/4

9:55 a.m.-11:45 a.m.

1 stop33h 50m

C$ 871

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 5/3

8:59 a.m.-11:05 a.m.

2 stops18h 06m

London Heathrow

Mon 9/3

7:40 a.m.-10:59 p.m.

2 stops22h 19m

C$ 873

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 24/3

12:25 p.m.-11:05 a.m.

1 stop15h 40m

London Heathrow

Fri 17/4

7:25 a.m.-4:59 p.m.

1 stop17h 34m

C$ 875

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 9/3

5:40 p.m.-10:30 a.m.

Nonstop9h 50m

London Heathrow

Mon 23/3

11:05 a.m.-8:50 p.m.

1 stop16h 45m

C$ 888

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 16/3

5:40 p.m.-10:30 a.m.

Nonstop9h 50m

London Heathrow

Tue 24/3

12:40 p.m.-10:22 p.m.

1 stop16h 42m

C$ 889

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/2

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 30 January 2026.

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 64 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 C$ 673). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,077). 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 3 February 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 3 February 2026.

The most flights from SEA to LON are scheduled on a Saturday (21 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (12 on average).

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 76% 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$ 726.

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 16% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 123 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 at night 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, 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 3 February 2026.
Get a feel of what it's like to fly with Virgin Atlantic,Air France, 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.
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Virgin Atlantic
7.5
Good
678 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Air France
7.4
Good
1,531 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Icelandair
7.1
Good
606 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Iberia
7.0
Good
3,103 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
British Airways
6.7
Okay
7,712 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Overall

7.5

Boarding

7.7

Comfort

7.3

Food

6.9

Entertainment

7.6

Crew

8.2

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!

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 15 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?

    Icelandair, KLM, and United Airlines can get you from Seattle to London in just under 9h 50m. Your travel time can differ by up to 3h 50m. 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, Iberia (C$ 620), Virgin Atlantic (C$ 623), and Icelandair (C$ 645) offers the cheapest pricing from Seattle to London. These flights start at 39% 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 American Airlines (78%), Alaska Airlines (78%) and Aer Lingus (78%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 441. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 1,165 on average, our data indicates C$ 874 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, May is the cheapest month in which you can book a flight from Seattle to London (average of C$ 673). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,077). 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
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Twickenham
Gatwick
Slough
Marlow
Cobham
Milton Keynes
Romford
Watford
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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 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 3 February 2026.
AirlineCheapestAverageFlexibilityOn-time
IberiaCheapestC$ 620AverageC$ 787FlexibilityNo cancel feeOn-time77%
Search Iberia flights
Virgin AtlanticCheapestC$ 623AverageC$ 940FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
IcelandairCheapestC$ 645AverageC$ 713FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
British AirwaysCheapestC$ 693AverageC$ 964FlexibilityNo cancel feeOn-time70%
Search British Airways 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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