Find flights
Deals
When to book
FAQs

Cheap flights from London Heathrow Airport to Seattle from C$ 720

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 9/2. Fares are subject to change and may not be available on all flights or dates of travel.
LHR — SEA
12 Sep — 19 Sep1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from London Heathrow to Seattle/Tacoma Intl are usually found in January or February, booked 57 days in advance, depart on a Tuesday or Thursday and return on a Saturday

Cheap flight deals from Heathrow to Seattle

Enter your travel dates to find the best prices.

Cheapest flights from Heathrow to Seattle
Explore the most affordable flight options available from Heathrow to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 13 August 2026.

Mon 28/91:05 p.m. -
1 stop30h 30m
Tue 29/91:56 p.m. -
1 stop13h 59m
Deal found 10/8C$ 936
Mon 28/128:35 p.m. -
1 stop28h 25m
Mon 11/12:35 p.m. -
1 stop12h 15m
Deal found 9/8C$ 938
Mon 24/89:25 p.m. -
1 stop22h 20m
Wed 10/32:35 p.m. -
1 stop12h 15m
Deal found 12/8C$ 940
Mon 7/91:05 p.m. -
2 stops30h 16m
Tue 8/95:13 p.m. -
1 stop34h 42m
Deal found 10/8C$ 945
Mon 28/128:35 p.m. -
1 stop28h 25m
Wed 13/12:35 p.m. -
1 stop20h 55m
Deal found 9/8C$ 946
Tue 29/91:05 p.m. -
1 stop15h 35m
Tue 6/107:00 p.m. -
1 stop17h 20m
Deal found 12/8C$ 950
Sun 27/128:35 p.m. -
1 stop28h 25m
Mon 11/12:35 p.m. -
1 stop20h 55m
Deal found 9/8C$ 951
Mon 28/99:25 p.m. -
1 stop31h 15m
Mon 5/103:40 p.m. -
1 stop12h 15m
Deal found 10/8C$ 953
Sun 6/99:25 p.m. -
1 stop22h 20m
Mon 21/93:40 p.m. -
1 stop12h 15m
Deal found 12/8C$ 960
Wed 2/91:05 p.m. -
1 stop12h 50m
Wed 16/97:00 p.m. -
1 stop17h 20m
Deal found 9/8C$ 961
Tue 1/91:05 p.m. -
1 stop15h 35m
Thu 24/97:00 p.m. -
1 stop32h 55m
Deal found 11/8C$ 963

Find flight deals from Heathrow to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Heathrow (LHR) to Seattle (SEA). 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 13 August 2026.

Round-trip from

C$ 936

One-way from

C$ 720

Popular in

July

Cheapest in

January

Average price

C$ 1,098

Good round-trip deal

C$ 1,327 or less
United Airlines
  • United Airlines
  • 28/9-29/9
  • 2 total stops
  • 44h 29m total
  • London to Seattle
Search Deals
United Airlines
  • United Airlines
  • 9/2
  • 2 total stops
  • 23h 33m total
  • London to Seattle
Search Deals
Highest demand for flights based on searches. 7% potential increase in price (C$ 126 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (C$ 20 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in August 2026
Search Deals
Price to beat on a round-trip flight from London Heathrow to Seattle/Tacoma Intl.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Heathrow to Seattle 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 13 August 2026.
Use the filters below to find and compare flights from London Heathrow Airport to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Wed 2/9

1:05 p.m.-5:55 p.m.

1 stop12h 50m

Seattle/Tacoma Intl

Tue 22/9

7:00 p.m.-8:20 p.m.

1 stop17h 20m

C$ 960

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Mon 5/10

6:00 a.m.-6:32 p.m.

2 stops20h 32m

Seattle/Tacoma Intl

Wed 21/10

7:00 a.m.-7:55 a.m.

2 stops16h 55m

C$ 988

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Wed 25/11

11:10 a.m.-11:15 p.m.

2 stops20h 05m

Seattle/Tacoma Intl

Mon 30/11

1:16 p.m.-1:30 p.m.

2 stops16h 14m

C$ 1,003
Quickest round-trip

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Tue 29/9

9:50 a.m.-11:35 a.m.

Nonstop9h 45m

Seattle/Tacoma Intl

Sun 11/10

3:14 p.m.-12:15 p.m.

1 stop13h 01m

C$ 1,074

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Tue 1/9

6:55 a.m.-5:42 p.m.

2 stops18h 47m

Seattle/Tacoma Intl

Mon 7/9

1:22 p.m.-11:10 a.m.

1 stop13h 48m

C$ 1,135

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Tue 25/8

8:55 a.m.-4:41 p.m.

1 stop15h 46m

Seattle/Tacoma Intl

Sun 13/9

1:30 p.m.-6:45 a.m.

Nonstop9h 15m

C$ 1,199

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Mon 5/10

9:05 p.m.-1:45 p.m.

2 stops24h 40m

Seattle/Tacoma Intl

Wed 21/10

10:51 a.m.-4:00 p.m.

2 stops21h 09m

C$ 1,252

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Fri 18/9

9:05 p.m.-1:45 p.m.

2 stops24h 40m

Seattle/Tacoma Intl

Sat 10/10

3:55 p.m.-6:30 p.m.

1 stop18h 35m

C$ 2,703

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Thu 1/10

10:20 a.m.-1:45 p.m.

1 stop35h 25m

Seattle/Tacoma Intl

Sat 10/10

3:55 p.m.-5:40 p.m.

1 stop17h 45m

C$ 2,711

LondonSeattle

LHR London Heathrow - SEA Seattle/Tacoma Intl

LHRSEA

London Heathrow

Tue 27/10

8:15 a.m.-11:16 a.m.

3 stops34h 01m

Seattle/Tacoma Intl

Sun 8/11

6:45 a.m.-9:35 p.m.

2 stops30h 50m

C$ 3,362

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/8

Showing 1-10 of 23 resultsSorted by cheapest first
1
2
3

Best time to book a flight from Heathrow to Seattle

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

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

The price you pay for your flight from London Heathrow Airport to Seattle may vary depending on when you book. For the best chance of a lower fare, look to book 56 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 London Heathrow Airport to Seattle?

Currently, January is the cheapest month in which you can book a flight from London Heathrow Airport to Seattle (average of C$ 914). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,247). 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 LHR to SEA?

Find hourly flight availability from Heathrow to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 13 August 2026.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from London Heathrow Airport to Seattle as you normally would.

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

Airfare is below average for this route at the moment.

London Heathrow Airport to Seattle flights typically cost between C$ 981 and C$ 1,276 in September.
The cheapest round-trip price found within the last 5 days was C$ 936 on United Airlines (28 Sep-29 Sep).

Related info for your journey

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

    Seattle/Tacoma Intl (SEA), located 18.4 km from the city centre, is the airport you fly into when you book flights from London Heathrow to Seattle. 0 airlines have flights to Seattle/Tacoma Intl from London Heathrow on a regular basis. Booking flights from London Heathrow to Seattle/Tacoma Intl should not be difficult; the airport handles an average of 19 inbound flights from London Heathrow per day.

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

    A quick flight from London Heathrow Airport to Seattle can take about 14h 09m. SWISS provides one of the quickest options available for as low as C$ 996. There are 7697 km between London Heathrow Airport and Seattle. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    Consider Scandinavian Airlines (85%), KLM (77%) or Air France (77%) when booking your flight. These represent the most reliable airlines when flying from London Heathrow Airport to Seattle.

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

    Looking for the cheapest flight from London Heathrow Airport to Seattle? While on average our users pay C$ 1,362, our data indicates the cheapest price to be C$ 1,118. The most popular route (London Heathrow - Seattle/Tacoma Intl), is priced around C$ 1,418.

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

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

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

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

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

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

    Currently, January is the cheapest month in which you can book a flight from London Heathrow Airport to Seattle (average of C$ 914). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,247). 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 Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Kent
Leavenworth
Mukilteo
Tacoma
Renton
Cashmere
Lynnwood
Ellensburg
Tukwila
Olympia
Marysville
Federal Way
Kirkland

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.

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 Heathrow to Seattle?

Deals for Heathrow to Seattle flights are sourced from 900+ travel sites when you use Cheapflights. When all flight results come back, Cheapflights lets you sort and filter flights using different criteria to choose better, like price, airport, cabin class, and plenty of other options.

Why should you use Cheapflights to find cheap flight tickets from Heathrow to Seattle?

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from Heathrow to Seattle for you. Better yet — we are completely free to use.

Can Cheapflights find flights from Heathrow to Seattle with no change fees?

Yes, we can. To see specific flights from Heathrow to Seattle with no change fees, users can toggle flexible booking options after using the search form above to find flights.

Can Cheapflights notify me if prices for flights from Heathrow to Seattle become cheaper?

Yes, Cheapflights has a feature called Price Alert, which notifies users when flight prices change. Track prices for your flight to Seattle from Heathrow today and book when prices fit your budget.

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.