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Cheap flights from Seattle to London from C$ 515

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 29/12. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
27 nov. — 4 dic.1
1 adult
1 adult, Economy, 0 bags

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or March, 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 28 octubre 2025.

Round-trip from

C$ 724

One-way from

C$ 515

Popular in

June

Cheapest in

October

Average price

C$ 927

Good round-trip deal

C$ 935 or less

Good one-way deal

C$ 481 or less
Icelandair
  • Icelandair
  • 5/3-13/3
  • 2 total stops
  • 25h 25m total
  • Seattle to London
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WestJet
  • WestJet
  • 29/12
  • 1 total stop
  • 13h 40m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (C$ 262 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 43 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 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 28 octubre 2025.

mar. 2/122:35 p.m.SEA - LHR
1 stop20h 55mIcelandair
vie. 23/112:15 p.m.LHR - SEA
1 stop12h 45mIcelandair
Deal found 27/10C$ 727
mar. 11/112:35 p.m.SEA - LHR
1 stop12h 15mIcelandair
lun. 17/118:35 p.m.LHR - SEA
1 stop28h 25mIcelandair
Deal found 27/10C$ 729
mié. 3/122:35 p.m.SEA - LHR
1 stop20h 55mIcelandair
mar. 20/18:35 p.m.LHR - SEA
1 stop28h 25mIcelandair
Deal found 27/10C$ 730
mar. 4/112:35 p.m.SEA - LGW
1 stop12h 20mIcelandair
vie. 14/1111:55 a.m.LGW - SEA
1 stop13h 05mIcelandair
Deal found 28/10C$ 755
mié. 3/124:48 p.m.SEA - LHR
Nonstop9h 42mDelta
jue. 22/16:20 a.m.LHR - SEA
1 stop13h 05mDelta
Deal found 27/10C$ 807
dom. 9/114:48 p.m.SEA - LHR
Nonstop9h 42mDelta
lun. 24/118:40 a.m.LHR - SEA
1 stop35h 05mDelta
Deal found 27/10C$ 808
lun. 27/1012:45 p.m.SEA - LHR
1 stop21h 05mDelta
mar. 11/116:20 a.m.LHR - SEA
1 stop13h 05mDelta
Deal found 26/10C$ 810
mié. 5/117:50 a.m.SEA - LHR
1 stop15h 00mDelta
mié. 12/116:20 a.m.LHR - SEA
1 stop15h 00mDelta
Deal found 28/10C$ 813
mié. 5/119:25 a.m.SEA - LHR
1 stop13h 40mMultiple Airlines
mar. 11/116:20 a.m.LHR - SEA
1 stop13h 05mMultiple Airlines
Deal found 28/10C$ 814
sáb. 8/119:59 p.m.SEA - LHR
1 stop24h 21mDelta
mié. 26/116:30 a.m.LHR - SEA
1 stop13h 15mDelta
Deal found 27/10C$ 815
mar. 2/126:50 p.m.SEA - LHR
Nonstop9h 30mBritish Airways
jue. 22/12:55 p.m.LHR - SEA
Nonstop10h 00mBritish Airways
Deal found 27/10C$ 817
lun. 10/114:48 p.m.SEA - LHR
Nonstop9h 42mDelta
vie. 28/1112:20 p.m.LHR - SEA
Nonstop10h 28mDelta
Deal found 27/10C$ 818

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 28 octubre 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

lun. 23/2

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

1 stop20h 55m

London Heathrow

mar. 3/3

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

lun. 1/12

2:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

sáb. 17/1

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

jue. 4/12

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

1 stop20h 55m

London Heathrow

mar. 20/1

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mié. 3/12

2:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

jue. 22/1

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

dom. 7/12

2:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

lun. 19/1

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mié. 25/2

2:35 p.m.-10:50 a.m.

1 stop12h 15m

London Heathrow

mar. 3/3

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

sáb. 6/12

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

1 stop20h 55m

London Heathrow

dom. 18/1

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

1 stop12h 45m

C$ 727

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

mar. 24/3

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

1 stop12h 20m

London Gatwick

mar. 31/3

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

1 stop13h 05m

C$ 754

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

mar. 24/3

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

1 stop12h 20m

London Gatwick

mié. 1/4

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

1 stop13h 05m

C$ 776

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

lun. 23/3

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

1 stop12h 20m

London Gatwick

vie. 3/4

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

1 stop13h 05m

C$ 776

Flights are sorted by cheapest round-trip flights first.

Deals found on 27/10

Showing 1-10 of 46 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 24 October 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, April is the cheapest month in which you can book a flight from Seattle to London (average of C$ 678). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,108). 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 28 octubre 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.

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 73% 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$ 709.

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 Reykjavik (KEF) offer the fastest connection on this route, with an average layover time of 1h 35m.

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 28 octubre 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
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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
670 reviews
Virgin Atlantic
7.5
Good
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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
1,482 reviews
Virgin Atlantic
7.5
Good
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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
562 reviews
Virgin Atlantic
7.5
Good
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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
3,001 reviews
Virgin Atlantic
7.5
Good
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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
7,483 reviews
Virgin Atlantic
7.5
Good
670 reviews
Check prices

Comfort

7.3

Boarding

7.7

Crew

8.1

Food

6.9

Overall

7.5

Entertainment

7.5

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 11 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 can get you from Seattle to London in just under 20h 55m. Your travel time can differ by up to . The distance between Seattle and London is about 7697 km.

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

    According to our current data, Icelandair (C$ 617), Virgin Atlantic (C$ 706), and British Airways (C$ 710) 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 (86%), Air France (86%) and Delta (86%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 345. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 1,253 on average, our data indicates C$ 1,363 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, April is the cheapest month in which you can book a flight from Seattle to London (average of C$ 678). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,108). 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
Hounslow
Slough
Marlow
Milton Keynes
Romford
Watford
Bedford
Luton
Gatwick

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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 28 octubre 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 617AverageC$ 772FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Virgin AtlanticCheapestC$ 706AverageC$ 1,003FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
British AirwaysCheapestC$ 710AverageC$ 1,106FlexibilityNo cancel feeOn-time70%
Search British Airways flights
IberiaCheapestC$ 732AverageC$ 868FlexibilityNo cancel feeOn-time77%
Search Iberia flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Seattle to London?

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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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