HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Heathrow

$363+ Cheap flights from Seattle (SEA) to Heathrow (LHR)

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 7/12. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
Jul 7 — Jul 141
Tue 7/7
Tue 7/14
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Seattle to Heathrow with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London Heathrow are usually found in January or October, booked 65 days in advance, depart on a Wednesday or Tuesday and return on a Monday

Cheap flight deals from Seattle to Heathrow

Cheapest flights from Seattle to Heathrow
Explore the most affordable flight options available from Seattle to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 7, 2026.

This KAYAK deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/47:20 pm
SEA
-
LHR
1 stop34h 00m
Lufthansa
Tue 7/78:30 am
LHR
-
SEA
2 stops18h 02m
Lufthansa
Deal found 6/2$887
This Air Canada deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1910:30 am
SEA
-
LHR
2 stops15h 30m
Air Canada
Fri 11/271:00 pm
LHR
-
SEA
2 stops28h 17m
Air Canada
Deal found 6/2$888
This Sembo deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Sembo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/127:00 pm
SEA
-
LHR
1 stop32h 55m
Multiple Airlines
Sat 7/259:50 am
LHR
-
SEA
Nonstop9h 45m
Multiple Airlines
Deal found 6/2$889
This Mytrip deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/27:00 pm
SEA
-
LHR
2 stops18h 35m
Multiple Airlines
Mon 9/77:05 am
LHR
-
SEA
2 stops21h 35m
Multiple Airlines
Deal found 6/2$891
This oojo deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/33:40 pm
SEA
-
LHR
1 stop12h 15m
Icelandair
Mon 7/139:25 pm
LHR
-
SEA
1 stop22h 20m
Icelandair
Deal found 6/2$892
This Booking.com deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/193:40 pm
SEA
-
LHR
1 stop12h 15m
Multiple Airlines
Wed 7/229:50 am
LHR
-
SEA
Nonstop9h 45m
Multiple Airlines
Deal found 6/2$893
This FlightHub deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/147:05 pm
SEA
-
LHR
2 stops30h 15m
Air Canada
Tue 12/19:00 am
LHR
-
SEA
2 stops19h 54m
Air Canada
Deal found 6/2$894
This oojo deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/183:55 pm
SEA
-
LHR
1 stop17h 45m
Scandinavian Airlines
Wed 9/307:30 pm
LHR
-
SEA
2 stops35h 20m
Scandinavian Airlines
Deal found 6/2$895
This KAYAK deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/197:20 pm
SEA
-
LHR
1 stop34h 00m
Lufthansa
Wed 7/228:30 am
LHR
-
SEA
2 stops16h 29m
Lufthansa
Deal found 6/2$896
This Cheapflightsfares deal was found by Cheapflights users on 6/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/1510:30 am
SEA
-
LHR
1 stop18h 50m
Lufthansa
Thu 10/226:30 am
LHR
-
SEA
2 stops15h 52m
Lufthansa
Deal found 6/3$897
This oojo deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 6/143:40 pm
SEA
-
LHR
1 stop12h 15m
Icelandair
Thu 6/259:25 pm
LHR
-
SEA
1 stop22h 20m
Icelandair
Deal found 6/2$898
This oojo deal was found by Cheapflights users on 6/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/267:00 pm
SEA
-
LHR
1 stop32h 55m
Icelandair
Wed 7/89:25 pm
LHR
-
SEA
1 stop22h 20m
Icelandair
Deal found 6/2$899

Find flight deals from Seattle to Heathrow

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Heathrow (LHR). 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 June 7, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$887
(KAYAK)

One-way from

$363
(Mytrip)

Popular in

June

Cheapest in

January

Average price

$1,205

Good round-trip deal

$1,034 or less

Good one-way deal

$469 or less
Provider with most accurate pricing for Seattle/Tacoma Intl-London Heathrow flight deals.
Search Deals
Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-London Heathrow flights.
Search Deals
From Seattle/Tacoma Intl to London Heathrow
Search Deals
One-way flight from Seattle/Tacoma Intl to London Heathrow
Search Deals
Highest demand for flights based on searches. 21% potential increase in price ($222 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($34 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to London Heathrow.
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to London Heathrow.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Heathrow 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 2,558,603 searches. Data last updated June 7, 2026.
Use the filters below to find and compare flights from Seattle to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 9/24

8:10 pm-2:00 pm

Nonstop9h 50m

London Heathrow

Thu 10/15

8:40 am-4:35 pm

1 stop15h 55m

$902

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 10/23

7:20 am-9:20 am

2 stops18h 00m

London Heathrow

Fri 10/30

6:40 am-12:09 am

2 stops24h 29m

$908

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 9/3

2:50 pm-6:30 pm

2 stops19h 40m

London Heathrow

Mon 9/7

7:30 pm-1:45 pm

1 stop26h 15m

$918
Quickest round-trip

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 8/30

1:30 pm-6:45 am

Nonstop9h 15m

London Heathrow

Wed 9/2

9:50 am-11:35 am

Nonstop9h 45m

$955

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 7/23

9:50 pm-3:35 pm

Nonstop9h 45m

London Heathrow

Thu 8/13

11:45 am-4:27 pm

1 stop12h 42m

$976

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 8/20

9:45 pm-3:35 pm

Nonstop9h 50m

London Heathrow

Thu 8/27

5:45 pm-8:03 pm

Nonstop10h 18m

$980

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 8/27

8:10 pm-2:00 pm

Nonstop9h 50m

London Heathrow

Sat 9/5

6:30 am-4:35 pm

1 stop18h 05m

$1,001

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 7/24

3:55 pm-6:30 pm

2 stops18h 35m

London Heathrow

Mon 8/3

9:05 pm-1:45 pm

2 stops24h 40m

$1,040

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 7/3

9:45 pm-3:05 pm

Nonstop9h 20m

London Heathrow

Fri 7/10

5:00 pm-6:45 pm

Nonstop9h 45m

$1,067

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 7/7

7:15 am-7:15 am

1 stop16h 00m

London Heathrow

Sun 7/19

11:45 am-4:20 pm

1 stop12h 35m

$1,071

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/6

Showing 1-10 of 24 resultsSorted by cheapest first
1
2
3

Compare providers for flights from Seattle to Heathrow

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to Heathrow in June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice Accuracy3 starsTrust Score*3 stars
OvagoPrice Accuracy3 starsTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star
BusinessClassPrice Accuracy-Trust Score*3 stars
eDreamsPrice Accuracy2 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy2 starsTrust Score*1 star
Justfly.comPrice Accuracy3 starsTrust Score*3 stars
Trip.comPrice Accuracy1 starTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Seattle-London Heathrow Airport flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-London Heathrow Airport flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-London Heathrow Airport flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Seattle-London Heathrow Airport flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London Heathrow Airport flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Seattle to Heathrow

Have a flexible travel schedule? Discover the best time to fly to Heathrow 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 Heathrow Airport

How far ahead should I book a flight from Seattle to London Heathrow Airport?

Booking 64 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to London Heathrow Airport. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Seattle to London Heathrow Airport?

Currently, January is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of $642). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $1,205). 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 LHR?

Find hourly flight availability from Seattle to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 7, 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 Heathrow Airport as you normally would.

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

The best insider tips for Seattle to London Heathrow Airport flights

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to London Heathrow Airport trip
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on LHR

An avid traveler and aviation expert who has visited 173 countries, all 50 states and seven continents, Ramsey Qubein flies nearly 400,000 miles a year. As a North Carolina-based freelance journalist for publications including Conde Nast Traveler, Forbes, USA Today and Bloomberg among others, he explores the latest trends in aviation, hospitality, cruises and business.

Read more
Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more

Reviews of airlines servicing Heathrow

Get insights into the airlines that provide service to Heathrow. 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 Heathrow. Reviews last updated June 7, 2026.
Read reviews from past customers who have flown Delta,Virgin Atlantic, andAir France from Seattle to London Heathrow Airport. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Delta
7.9
Good
8,397 reviews
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Virgin Atlantic
7.5
Good
689 reviews
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Air France
7.4
Good
1,597 reviews
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Icelandair
7.0
Good
667 reviews
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
British Airways
6.7
Okay
8,028 reviews
Delta
7.9
Good
8,397 reviews

Boarding

8.1

Overall

7.9

Crew

8.5

Comfort

7.8

Food

7.2

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional

Related info for your journey

Find useful and relevant information for your journey from Seattle to Heathrow. 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 Heathrow?

    Seattle/Tacoma Intl (SEA) is the airport you will fly out of if you book a flight from Seattle to London Heathrow. You should not have trouble finding flights to London Heathrow from Seattle/Tacoma Intl; the airport handles an average of 22 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 13 airlines have flights from the Seattle airport to London Heathrow. It is only a 11.4 mi journey to Seattle/Tacoma Intl (SEA) from Seattle’s city center.

  • How long is the flight from Seattle to London Heathrow Airport?

    For as low as $955, KLM can have you in London Heathrow Airport from Seattle in 9h 15m. The distance between Seattle and London Heathrow Airport is about 4783 mi. This flight may include one or multiple stops.

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

    Our cheapest airline available from Seattle to London Heathrow Airport is Aer Lingus. Our recent data shows that you can find tickets from as low as $480 on this airline. Additional options worth looking into are Icelandair and American Airlines, starting at $483 and $515 round-trip. Aer Lingus is currently priced 42% below the average price you’ll pay for this route.

  • What are the cheapest airlines to fly from Seattle to London Heathrow Airport one-way?

    The cheapest airlines for a one-way flight from Seattle to London Heathrow Airport are Icelandair ($161), WestJet ($231), and Aer Lingus ($321).

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

    No one likes to see their flight delayed. When booking a flight from Seattle to London Heathrow Airport consider choosing KLM (93%), Air France (93%) or Delta (93%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Seattle to London Heathrow Airport?

    Looking for the cheapest flight from Seattle to London Heathrow Airport? While on average our users pay $2,499, our data indicates the cheapest price to be $366. The most popular route (Seattle/Tacoma Intl - London Heathrow), is priced around $639.

  • Can I find deals for flights from Seattle to Heathrow that include hotel bookings?

    Yes. In addition to deals on Seattle to Heathrow flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Heathrow?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Heathrow.

  • Can I find deals for business class flights from Seattle to Heathrow?

    Yes. Cheapflights offers flight deals from Seattle to Heathrow 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 Heathrow Airport?

    Currently, January is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of $642). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $1,205). 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

Traveling to a place near London Heathrow Airport?

Book flights to London Heathrow Airport if you plan to visit one of these locations
Ilford
Dorking
Hounslow
Winchester
Croydon
Gatwick
Southend-on-Sea
Wembley
Harrow
Eastleigh
Dartford
Dover
Orpington
Watford
Northampton
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Slough

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 10 airlines flying from Seattle to Heathrow

Discover the top 10 airlines that operate flights from Seattle to Heathrow. 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 2,558,603 searches. Data last updated June 7, 2026.
AirlineCheapestAverageFlexibilityOn-time
Aer LingusCheapest$480Average$628FlexibilityNo cancel feeOn-timeN/A
IcelandairCheapest$483Average$662FlexibilityNo cancel feeOn-time76%
American AirlinesCheapest$515Average$789FlexibilityNo cancel feeOn-time71%
Air FranceCheapest$517Average$762FlexibilityNo cancel feeOn-time77%
British AirwaysCheapest$524Average$725FlexibilityNo cancel feeOn-time70%
DeltaCheapest$545Average$874FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$547Average$842FlexibilityNo cancel feeOn-time69%
FinnairCheapest$556Average$694FlexibilityNo cancel feeOn-time76%
Virgin AtlanticCheapest$566Average$942FlexibilityNo cancel feeOn-time72%
Alaska AirlinesCheapest$589Average$1,051FlexibilityNo cancel feeOn-time75%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.
Site
©2026 Cheapflights