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Cheap flights from London Heathrow Airport to Seattle from C$ 798

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 12/11. Fares are subject to change and may not be available on all flights or dates of travel.
LHR — SEA
25 Jul — 1 Aug1
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 81 days in advance, depart on a Monday or Wednesday and return on a Wednesday

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 25 June 2026.

Thu 9/79:00 a.m.
LHR
-
SEA
1 stop15h 59m
United Airlines
Sat 1/811:00 p.m.
SEA
-
LHR
1 stop14h 20m
United Airlines
Deal found 24/6C$ 892
Thu 9/79:00 a.m.
LHR
-
SEA
1 stop15h 59m
United Airlines
Thu 30/73:40 p.m.
SEA
-
LHR
1 stop12h 45m
United Airlines
Deal found 23/6C$ 893
Fri 16/106:30 a.m.
LHR
-
SEA
1 stop13h 50m
Lufthansa
Mon 2/118:10 a.m.
SEA
-
LHR
1 stop14h 30m
Lufthansa
Deal found 24/6C$ 895
Sun 20/96:30 a.m.
LHR
-
SEA
1 stop13h 25m
Lufthansa
Sat 26/91:56 p.m.
SEA
-
LHR
1 stop13h 59m
Lufthansa
Deal found 22/6C$ 896
Tue 25/87:40 a.m.
LHR
-
SEA
1 stop17h 30m
British Airways
Sun 6/97:40 a.m.
SEA
-
LHR
1 stop17h 20m
British Airways
Deal found 24/6C$ 898
Sun 20/96:20 a.m.
LHR
-
SEA
1 stop18h 50m
British Airways
Sat 26/91:30 p.m.
SEA
-
LHR
Nonstop9h 15m
British Airways
Deal found 22/6C$ 899
Sat 24/109:50 a.m.
LHR
-
SEA
Nonstop9h 45m
British Airways
Sat 31/102:35 p.m.
SEA
-
LHR
Nonstop9h 35m
British Airways
Deal found 24/6C$ 901
Tue 27/102:55 p.m.
LHR
-
SEA
Nonstop10h 00m
British Airways
Sun 8/116:50 p.m.
SEA
-
LHR
Nonstop9h 30m
British Airways
Deal found 23/6C$ 902
Fri 4/96:50 a.m.
LHR
-
SEA
2 stops19h 51m
United Airlines
Sun 6/98:10 a.m.
SEA
-
LHR
1 stop14h 45m
United Airlines
Deal found 22/6C$ 905
Mon 21/96:50 a.m.
LHR
-
SEA
2 stops19h 51m
United Airlines
Mon 28/912:43 p.m.
SEA
-
LHR
1 stop15h 42m
United Airlines
Deal found 21/6C$ 906
Sat 27/66:30 a.m.
LHR
-
SEA
1 stop17h 54m
Delta
Fri 10/79:50 p.m.
SEA
-
LHR
Nonstop9h 45m
Delta
Deal found 24/6C$ 908

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 25 June 2026.

Round-trip from

C$ 892

One-way from

C$ 798

Popular in

July

Cheapest in

January

Average price

C$ 1,249

Good round-trip deal

C$ 1,061 or less
United Airlines
  • United Airlines
  • 26/8-4/9
  • 3 total stops
  • 36h 34m total
  • London to Seattle
Search Deals
United Airlines
  • United Airlines
  • 12/11
  • 3 total stops
  • 23h 46m total
  • London to Seattle
Search Deals
Highest demand for flights based on searches. 10% potential increase in price (C$ 178 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (C$ 26 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 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 25 June 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
Quickest round-trip

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 15/10

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

Nonstop9h 45m

Seattle/Tacoma Intl

Mon 19/10

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

Nonstop9h 15m

C$ 933

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sun 23/8

6:30 p.m.-8:46 p.m.

Nonstop10h 16m

Seattle/Tacoma Intl

Wed 2/9

9:50 p.m.-3:35 p.m.

Nonstop9h 45m

C$ 990

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 20/8

6:30 a.m.-11:37 a.m.

1 stop13h 07m

Seattle/Tacoma Intl

Tue 1/9

6:20 p.m.-12:10 p.m.

Nonstop9h 50m

C$ 1,003

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 4/9

6:30 a.m.-11:47 a.m.

1 stop13h 17m

Seattle/Tacoma Intl

Mon 7/9

6:20 p.m.-12:10 p.m.

Nonstop9h 50m

C$ 1,030

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 16/7

8:00 a.m.-7:06 p.m.

1 stop19h 06m

Seattle/Tacoma Intl

Thu 13/8

5:00 a.m.-6:45 a.m.

2 stops17h 45m

C$ 1,040

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 27/7

6:00 p.m.-11:57 a.m.

1 stop25h 57m

Seattle/Tacoma Intl

Sat 8/8

5:00 a.m.-11:10 a.m.

1 stop22h 10m

C$ 1,040

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 21/8

5:45 p.m.-8:03 p.m.

Nonstop10h 18m

Seattle/Tacoma Intl

Fri 4/9

9:50 p.m.-3:35 p.m.

Nonstop9h 45m

C$ 1,056

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 10/8

5:45 p.m.-8:03 p.m.

Nonstop10h 18m

Seattle/Tacoma Intl

Thu 20/8

5:30 a.m.-7:10 a.m.

1 stop17h 40m

C$ 1,077

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 14/9

5:00 p.m.-7:00 p.m.

Nonstop10h 00m

Seattle/Tacoma Intl

Mon 21/9

9:40 p.m.-3:05 p.m.

Nonstop9h 25m

C$ 1,085

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 6/8

5:45 p.m.-8:03 p.m.

Nonstop10h 18m

Seattle/Tacoma Intl

Thu 13/8

9:45 p.m.-3:35 p.m.

Nonstop9h 50m

C$ 1,091

Flights are sorted by cheapest round-trip flights first.

Deals found on 20/6

Showing 1-10 of 22 resultsSorted by cheapest first
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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 80 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$ 946). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,314). 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 25 June 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?

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 21 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 10h 05m. British Airways provides one of the quickest options available for as low as C$ 902. 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 KLM (85%), Air France (85%) or Delta (85%) 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$ 1,105, our data indicates the cheapest price to be C$ 1,061. The most popular route (London Heathrow - Seattle/Tacoma Intl), is priced around C$ 1,448.

  • 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$ 946). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,314). 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
Tukwila
Olympia
Marysville
Federal Way
Kirkland

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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.

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