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Cheap flights from London Heathrow Airport to Seattle from C$ 735

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 5/9. Fares are subject to change and may not be available on all flights or dates of travel.
LHR — SEA
28 May — 4 Jun1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from London Heathrow to Seattle/Tacoma Intl are usually found in February or January, booked 58 days in advance, depart on a Monday or Tuesday 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 28 April 2026.

Wed 27/59:25 p.m.
LHR
-
SEA
1 stop22h 20m
Icelandair
Tue 2/63:40 p.m.
SEA
-
LHR
1 stop20h 40m
Icelandair
Deal found 24/4C$ 960
Wed 24/69:25 p.m.
LHR
-
SEA
1 stop22h 20m
Icelandair
Wed 8/711:25 p.m.
SEA
-
LHR
1 stop12h 55m
Icelandair
Deal found 23/4C$ 961
Thu 25/69:25 p.m.
LHR
-
SEA
1 stop22h 20m
Icelandair
Sun 12/73:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Deal found 26/4C$ 962
Wed 24/69:25 p.m.
LHR
-
SEA
1 stop22h 20m
Icelandair
Mon 6/711:25 p.m.
SEA
-
LHR
1 stop28h 30m
Icelandair
Deal found 23/4C$ 964
Tue 23/61:05 p.m.
LHR
-
SEA
1 stop15h 35m
Icelandair
Mon 6/711:25 p.m.
SEA
-
LHR
1 stop28h 30m
Icelandair
Deal found 26/4C$ 965
Sun 31/59:25 p.m.
LHR
-
SEA
1 stop31h 15m
Icelandair
Tue 16/611:25 p.m.
SEA
-
LHR
1 stop12h 55m
Icelandair
Deal found 28/4C$ 966
Tue 19/59:25 p.m.
LHR
-
SEA
1 stop28h 30m
Icelandair
Sun 31/57:00 p.m.
SEA
-
LHR
1 stop32h 55m
Icelandair
Deal found 26/4C$ 968
Thu 7/51:05 p.m.
LHR
-
SEA
1 stop12h 50m
Icelandair
Wed 20/511:25 p.m.
SEA
-
LHR
1 stop12h 55m
Icelandair
Deal found 23/4C$ 1,002
Wed 29/49:25 p.m.
LHR
-
SEA
1 stop31h 15m
Icelandair
Thu 7/57:00 p.m.
SEA
-
LHR
1 stop17h 20m
Icelandair
Deal found 24/4C$ 1,017
Mon 4/59:25 p.m.
LHR
-
SEA
1 stop31h 15m
Icelandair
Thu 21/511:25 p.m.
SEA
-
LHR
1 stop28h 30m
Icelandair
Deal found 23/4C$ 1,021
Sat 26/91:05 p.m.
LHR
-
SEA
1 stop15h 35m
Icelandair
Sun 27/93:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Deal found 24/4C$ 1,025
Thu 30/49:25 p.m.
LHR
-
SEA
1 stop28h 30m
Icelandair
Sat 9/53:40 p.m.
SEA
-
LHR
1 stop12h 15m
Icelandair
Deal found 24/4C$ 1,028

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 28 April 2026.

Round-trip from

C$ 960

One-way from

C$ 735

Popular in

July

Cheapest in

February

Average price

C$ 1,130

Good one-way deal

C$ 857 or less
Icelandair
  • Icelandair
  • 28/5-2/6
  • 2 total stops
  • 43h 00m total
  • London to Seattle
Search Deals
British Airways
  • British Airways
  • 5/9
  • 2 total stops
  • 52h 45m total
  • London to Seattle
Search Deals
Highest demand for flights based on searches. 10% potential increase in price (C$ 174 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 30 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2026
Search Deals
Price to beat on a one-way 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 28 April 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 - SEA

LHRSEA

London Heathrow

Thu 28/5

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

2 stops24h 40m

Seattle/Tacoma Intl

Sat 6/6

3:55 p.m.-6:50 p.m.

2 stops18h 55m

C$ 1,062

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 8/6

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

1 stop13h 07m

Seattle/Tacoma Intl

Mon 15/6

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

Nonstop9h 50m

C$ 1,070

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sat 26/9

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

1 stop13h 17m

Seattle/Tacoma Intl

Thu 22/10

8:10 p.m.-2:00 p.m.

Nonstop9h 50m

C$ 1,073

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 16/7

6:15 a.m.-11:15 a.m.

1 stop13h 00m

Seattle/Tacoma Intl

Fri 31/7

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

Nonstop9h 50m

C$ 1,091

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 25/8

11:30 a.m.-5:34 p.m.

1 stop14h 04m

Seattle/Tacoma Intl

Wed 2/9

11:50 a.m.-10:40 a.m.

1 stop14h 50m

C$ 1,125
Quickest round-trip

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 11/6

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

Nonstop9h 45m

Seattle/Tacoma Intl

Tue 16/6

9:45 p.m.-3:05 p.m.

Nonstop9h 20m

C$ 1,129

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 4/9

9:55 a.m.-4:35 p.m.

1 stop14h 40m

Seattle/Tacoma Intl

Mon 7/9

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

Nonstop9h 45m

C$ 1,145

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 6/8

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

1 stop13h 07m

Seattle/Tacoma Intl

Sun 13/9

5:40 p.m.-5:30 p.m.

1 stop15h 50m

C$ 1,145

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 12/6

6:30 a.m.-4:24 p.m.

1 stop17h 54m

Seattle/Tacoma Intl

Mon 22/6

10:05 p.m.-3:35 p.m.

Nonstop9h 30m

C$ 1,152

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sun 16/8

6:15 a.m.-11:15 a.m.

1 stop13h 00m

Seattle/Tacoma Intl

Mon 31/8

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

Nonstop9h 50m

C$ 1,153

Flights are sorted by cheapest round-trip flights first.

Deals found on 27/4

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 57 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, February is the cheapest month in which you can book a flight from London Heathrow Airport to Seattle (average of C$ 889). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,292). 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 28 April 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 18 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 13h 07m. Delta provides one of the quickest options available for as low as C$ 1,070. 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 (95%), Delta (94%) or Virgin Atlantic (94%) 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$ 857, our data indicates the cheapest price to be C$ 855. 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, February is the cheapest month in which you can book a flight from London Heathrow Airport to Seattle (average of C$ 889). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of C$ 1,292). 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
Leavenworth
Mukilteo
Kent
Tacoma
Bothell
Cashmere
Olympia
Renton
Marysville
Lynnwood
Kirkland
Tukwila

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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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