HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Heathrow

$254+ 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 10/27. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 March or April, booked 32 days in advance, depart on a Tuesday or Monday and return on a Wednesday

Cheap 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 12, 2025.

Round-trip from

$665
(Delta)

One-way from

$257
(oojo)

Popular in

June

Cheapest in

March

Average price

$1,115

Good round-trip deal

$665 or less

Good one-way deal

$445 or less
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. 17% potential increase in price ($178 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($28 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2025
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

Find 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 12, 2025.

This Delta deal was found by Cheapflights users on 6/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/65:10 pmSEA - LHR
1 stop14h 30mDelta
Tue 10/215:25 pmLHR - SEA
Nonstop10h 25mDelta
Deal found 6/11$665
This Icelandair deal was found by Cheapflights users on 6/10. 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 Icelandair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/243:45 pmSEA - LHR
1 stop12h 10mIcelandair
Mon 9/159:25 pmLHR - SEA
1 stop28h 25mIcelandair
Deal found 6/10$666
This SWISS deal was found by Cheapflights users on 6/10. 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 SWISS is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2710:00 amSEA - LHR
2 stops22h 25mSWISS
Thu 9/115:10 pmLHR - SEA
2 stops33h 26mSWISS
Deal found 6/10$667
This United Airlines deal was found by Cheapflights users on 6/11. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/187:34 pmSEA - LHR
2 stops17h 06mUnited Airlines
Thu 8/287:30 amLHR - SEA
2 stops18h 27mUnited Airlines
Deal found 6/11$668
This Finnair deal was found by Cheapflights users on 6/10. 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 Finnair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/271:30 pmSEA - LHR
Nonstop9h 20mFinnair
Mon 8/119:30 amLHR - SEA
1 stop14h 30mFinnair
Deal found 6/10$669
This Air France deal was found by Cheapflights users on 6/9. 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 France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/118:25 pmSEA - LHR
Nonstop9h 50mAir France
Thu 7/245:25 pmLHR - SEA
Nonstop10h 20mAir France
Deal found 6/9$675
This Virgin Atlantic deal was found by Cheapflights users on 6/11. 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 Virgin Atlantic is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/87:45 amSEA - LHR
1 stop15h 00mVirgin Atlantic
Tue 10/76:15 amLHR - SEA
1 stop13h 00mVirgin Atlantic
Deal found 6/11$676
This Lufthansa deal was found by Cheapflights users on 6/10. 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 Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/1910:00 amSEA - LHR
2 stops17h 50mLufthansa
Wed 1/77:15 pmLHR - SEA
2 stops24h 55mLufthansa
Deal found 6/10$678
This FlightHub deal was found by Cheapflights users on 6/11. 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.
Fri 8/154:00 pmSEA - LHR
1 stop33h 20mScandinavian Airlines
Sat 8/3010:20 amLHR - SEA
1 stop35h 30mScandinavian Airlines
Deal found 6/11$679
This FlightHub deal was found by Cheapflights users on 6/11. 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.
Sun 7/275:30 amSEA - LHR
2 stops22h 20mMultiple Airlines
Sun 8/108:05 pmLHR - SEA
1 stop26h 50mMultiple Airlines
Deal found 6/11$681
This Air Canada deal was found by Cheapflights users on 6/11. 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.
Sun 8/247:20 amSEA - LHR
1 stop18h 40mAir Canada
Mon 9/155:10 pmLHR - SEA
2 stops33h 26mAir Canada
Deal found 6/11$686
This Cheapflightsfares deal was found by Cheapflights users on 6/12. 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.
Mon 9/221:30 pmSEA - LHR
Nonstop9h 20mBritish Airways
Mon 10/69:50 amLHR - SEA
Nonstop9h 45mBritish Airways
Deal found 6/12$687

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 12, 2025.
Use the filters below to find and compare flights from Seattle to London Heathrow Airport that are best for you.

Fly from

Seattle

Fly to

Heathrow

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 10/6

5:10 pm-3:40 pm

1 stop14h 30m

London Heathrow

Tue 10/21

5:25 pm-7:50 pm

Nonstop10h 25m

$665

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 8/27

10:00 am-4:25 pm

2 stops22h 25m

London Heathrow

Wed 9/10

5:10 pm-6:36 pm

2 stops33h 26m

$667

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 8/18

7:34 pm-8:40 pm

2 stops17h 06m

London Heathrow

Thu 8/28

7:30 am-5:57 pm

2 stops18h 27m

$668

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 7/27

8:20 pm-1:40 pm

Nonstop9h 20m

London Heathrow

Mon 8/11

7:30 am-4:00 pm

1 stop16h 30m

$669

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 7/11

8:25 pm-2:15 pm

Nonstop9h 50m

London Heathrow

Thu 7/24

5:25 pm-7:45 pm

Nonstop10h 20m

$675

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 7/8

7:45 am-6:45 am

1 stop15h 00m

London Heathrow

Tue 10/7

6:15 am-11:15 am

1 stop13h 00m

$676

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 8/19

10:00 am-11:50 am

2 stops17h 50m

London Heathrow

Wed 1/7

7:15 pm-12:10 pm

2 stops24h 55m

$678

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 8/15

4:00 pm-9:20 am

1 stop33h 20m

London Heathrow

Tue 8/26

5:00 pm-1:50 pm

1 stop28h 50m

$679

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 10/9

7:00 pm-8:20 pm

1 stop17h 20m

London Heathrow

Thu 11/20

8:40 pm-5:00 pm

1 stop28h 20m

$680

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 7/27

5:30 am-11:50 am

2 stops22h 20m

London Heathrow

Sun 8/10

8:05 pm-2:55 pm

1 stop26h 50m

$681

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 27 results
1
2
3

The best insider tips for Seattle to London Heathrow Airport flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to London Heathrow Airport trip
Airports
SEA

Use SEA Spot Saver to book security screening appointments in advance, reducing wait times without needing TSA PreCheck or CLEAR.

Read more about SEAby Brandon Schultz
LHR

Take the Heathrow Express for the fastest route to central London, reaching Paddington Station quickly and conveniently.

Read more about LHRby Ramsey Qubein
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on LHR

Ramsey Qubein

Ramsey Qubein

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

Brandon Schultz

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

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?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Heathrow. Price data was last updated on June 9, 2025.

Booking 32 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, November is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of $661). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $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 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 12, 2025.

When flying from Seattle to London Heathrow Airport, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 12% versus a flight in the morning.

What is the cheapest day to fly from Seattle to London Heathrow Airport?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Heathrow. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Seattle to London Heathrow Airport flight should consider departing on Monday mornings when fares are most often at their lowest. Thursday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Seattle to London Heathrow Airport

Explore weekly flight availability from Seattle to Heathrow. 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 June 12, 2025.

The most flights from SEA to LHR are scheduled on a Monday (22 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (16 on average).

Rainfall in Heathrow by month

Plan your trip to Heathrow by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in London Heathrow Airport ranges from 1.6 - 2.8 inches per month. January is typically the wettest month, when rainfall can reach 2.8 in. July is typically the driest time to visit London Heathrow Airport when rainfall is around 1.6 in.

Temperature in Heathrow by month

Plan your trip to Heathrow by taking into account the average temperature totals by month.

If weather is an important factor for your trip to London Heathrow Airport, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 62.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 39.2 F).

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 12, 2025.
Peruse reviews from past customers who have flown with Delta, KLM and Finnair from Seattle to London to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Delta
8.0
Very good
7,950 reviews
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
KLM
7.8
Good
1,358 reviews
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Finnair
7.6
Good
1,290 reviews
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Air France
7.5
Good
1,463 reviews
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
SWISS
7.5
Good
1,623 reviews
Delta
8.0
Very good
7,950 reviews

Food

7.3

Boarding

8.2

Entertainment

7.9

Overall

8.0

Comfort

7.9

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

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 21 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 15 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.

  • 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 Delta. Our recent data shows that you can find tickets from as low as $665 on this airline. Additional options worth looking into are Scandinavian Airlines and SWISS, starting at $666 and $667 round-trip. Delta is currently priced 18% 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 ($257), JetBlue ($369), and Air Canada ($387).

  • 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 Aeromexico (92%), KLM (87%) or Air France (87%) 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 $2,939, our data indicates the cheapest price to be $380. The most popular route (Seattle/Tacoma Intl - London Heathrow), is priced around $435.

  • 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, November is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of $661). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $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

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Hayes
Hounslow
Thornton Heath
Luton
Canterbury
Harrow
Dover
Stratford-upon-Avon
Gatwick
Orpington
Watford
Northampton
Croydon
Folkestone
Borehamwood
Broadway
Sutton
Aylesbury
Chelmsford
Brentwood

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 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$378Average$819FlexibilityNo cancel feeOn-time76%
IcelandairCheapest$503Average$663FlexibilityNo cancel feeOn-time76%
Scandinavian AirlinesCheapest$532Average$741FlexibilityNo cancel feeOn-time77%
United AirlinesCheapest$550Average$881FlexibilityNo cancel feeOn-time69%
IberiaCheapest$579Average$734FlexibilityNo cancel feeOn-time77%
Aer LingusCheapest$583Average$794FlexibilityNo cancel feeOn-timeN/A
FinnairCheapest$597Average$728FlexibilityNo cancel feeOn-time76%
Air FranceCheapest$597Average$876FlexibilityNo cancel feeOn-time77%
KLMCheapest$597Average$833FlexibilityNo cancel feeOn-time75%
British AirwaysCheapest$611Average$856FlexibilityNo cancel feeOn-time70%

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.