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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 8/1. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
11 Dec — 18 Dec1
1 adult
1 adult, Economy, 0 bags

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or November, booked 9 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 11 November 2025.

Round-trip from

C$ 774

One-way from

C$ 509

Popular in

June

Cheapest in

October

Average price

C$ 927

Good round-trip deal

C$ 959 or less

Good one-way deal

C$ 482 or less
Icelandair
  • Icelandair
  • 18/3-5/4
  • 2 total stops
  • 25h 25m total
  • Seattle to London
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8/1
  • 8/1
  • 1 total stop
  • 34h 54m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (C$ 271 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (C$ 45 potential savings vs. average RT price).
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Average for round-trip flights in November 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 11 November 2025.

Wed 3/124:48 p.m.SEA - LHR
Nonstop9h 42mDelta
Wed 10/126:20 a.m.LHR - SEA
1 stop15h 05mDelta
Deal found 10/11C$ 805
Tue 2/127:20 p.m.SEA - LHR
Nonstop9h 30mDelta
Thu 11/126:30 a.m.LHR - SEA
1 stop13h 20mDelta
Deal found 10/11C$ 806
Tue 30/124:48 p.m.SEA - LHR
Nonstop9h 42mDelta
Tue 13/16:20 a.m.LHR - SEA
1 stop13h 05mDelta
Deal found 9/11C$ 809
Wed 12/1111:56 a.m.SEA - LHR
1 stop12h 49mMultiple Airlines
Wed 19/116:20 a.m.LHR - SEA
1 stop15h 00mMultiple Airlines
Deal found 10/11C$ 810
Wed 12/119:28 a.m.SEA - LHR
1 stop13h 37mMultiple Airlines
Thu 20/116:20 a.m.LHR - SEA
1 stop13h 05mMultiple Airlines
Deal found 10/11C$ 812
Mon 1/127:20 p.m.SEA - LHR
Nonstop9h 30mDelta
Fri 12/1212:20 p.m.LHR - SEA
Nonstop10h 38mDelta
Deal found 10/11C$ 815
Mon 29/122:35 p.m.SEA - LHR
1 stop20h 55mIcelandair
Sun 11/18:35 p.m.LHR - SEA
1 stop28h 25mIcelandair
Deal found 9/11C$ 817
Wed 31/1211:36 a.m.SEA - LHR
1 stop14h 39mDelta
Tue 13/112:20 p.m.LHR - SEA
Nonstop10h 33mDelta
Deal found 9/11C$ 819
Mon 1/1211:55 p.m.SEA - LHR
1 stop23h 10mDelta
Thu 18/1212:20 p.m.LHR - SEA
Nonstop10h 38mDelta
Deal found 9/11C$ 822
Tue 30/124:48 p.m.SEA - LHR
Nonstop9h 42mDelta
Fri 9/19:40 a.m.LHR - SEA
1 stop20h 33mDelta
Deal found 9/11C$ 826
Sun 30/112:35 p.m.SEA - LGW
1 stop12h 20mIcelandair
Mon 15/1211:55 a.m.LGW - SEA
1 stop13h 05mIcelandair
Deal found 9/11C$ 879
Tue 11/112:35 p.m.SEA - LGW
1 stop12h 20mIcelandair
Wed 26/1111:55 a.m.LGW - SEA
1 stop13h 05mIcelandair
Deal found 8/11C$ 886

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 11 November 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

Wed 18/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Sun 5/4

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 774

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 18/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Thu 9/4

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 774

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 6/5

3:45 p.m.-11:45 a.m.

1 stop12h 00m

London Gatwick

Sun 17/5

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 792

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 30/12

9:35 a.m.-10:00 a.m.

1 stop16h 25m

London Heathrow

Tue 13/1

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

1 stop13h 05m

C$ 809

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 29/12

2:35 p.m.-7:30 p.m.

1 stop20h 55m

London Heathrow

Mon 12/1

12:15 p.m.-5:00 p.m.

1 stop12h 45m

C$ 815

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 11/1

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Tue 20/1

2:55 p.m.-4:55 p.m.

Nonstop10h 00m

C$ 826

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Thu 19/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Wed 8/4

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 827

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Thu 19/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Sun 5/4

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 827

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Thu 19/3

3:35 p.m.-10:55 a.m.

1 stop12h 20m

London Gatwick

Thu 9/4

3:40 p.m.-8:45 p.m.

1 stop13h 05m

C$ 827

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 5/1

6:05 a.m.-8:45 a.m.

1 stop18h 40m

London Heathrow

Fri 16/1

12:20 p.m.-2:53 p.m.

Nonstop10h 33m

C$ 830

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/11

Showing 1-10 of 45 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 7 November 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, May is the cheapest month in which you can book a flight from Seattle to London (average of C$ 693). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,109). 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 11 November 2025.

It’s optimal to fly from Seattle to London in the morning. By choosing this option you can save up to 17% on the cost of your flight, compared to a flight at noon.

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 11 November 2025.

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).

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

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 11 November 2025.
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
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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
673 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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
1,486 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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
578 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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
3,008 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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
7,511 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Crew

8.1

Comfort

7.3

Boarding

7.7

Entertainment

7.5

Overall

7.5

Food

6.9

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, Delta, and British Airways can get you from Seattle to London in just under 9h 30m. Your travel time can differ by up to 6h 55m. 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, Icelandair (C$ 618), Virgin Atlantic (C$ 708), and British Airways (C$ 712) 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 (89%), Air France (84%) and Delta (84%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 346. While the most popular route (Seattle/Tacoma Intl - London Gatwick) can be booked for C$ 738 on average, our data indicates C$ 1,413 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$ 693). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,109). 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
Sutton
Twickenham
Slough
Marlow
Milton Keynes
Romford
Watford
Bedford
Luton
Gatwick
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 Gatwick flights
Seattle to Heathrow 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 11 November 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 618AverageC$ 774FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Virgin AtlanticCheapestC$ 708AverageC$ 1,005FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
British AirwaysCheapestC$ 712AverageC$ 1,109FlexibilityNo cancel feeOn-time70%
Search British Airways flights
IberiaCheapestC$ 734AverageC$ 870FlexibilityNo 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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