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Cheap flights from London Heathrow Airport to Seattle from C$ 696

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 10/12. Fares are subject to change and may not be available on all flights or dates of travel.
LHR — SEA
11 Oct — 18 Oct1
1 adult
1 adult, Economy

Cheapflights Tip: The best prices from London Heathrow to Seattle/Tacoma Intl are usually found in February or November, booked 62 days in advance, depart on a Monday or Tuesday and return on a Sunday

Cheap 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 11 September 2025.

Round-trip from

C$ 847

One-way from

C$ 696

Popular in

July

Cheapest in

February

Average price

C$ 959

Good round-trip deal

C$ 1,059 or less

Good one-way deal

C$ 1,031 or less
Icelandair
  • Icelandair
  • 7/10-12/11
  • 2 total stops
  • 36h 30m total
  • London to Seattle
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British Airways
  • British Airways
  • 8/12
  • Nonstop
  • 10h 00m total
  • London to Seattle
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Highest demand for flights based on searches. 12% potential increase in price (C$ 212 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 35 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from London Heathrow to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from London Heathrow to Seattle/Tacoma Intl.
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Find flight deals from Heathrow to Seattle

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 11 September 2025.

Thu 18/98:40 a.m.LHR - SEA
2 stops20h 14mSWISS
Tue 30/91:00 p.m.SEA - LHR
2 stops20h 50mSWISS
Deal found 10/9C$ 841
Tue 7/101:05 p.m.LHR - SEA
1 stop15h 35mIcelandair
Wed 12/112:35 p.m.SEA - LHR
1 stop20h 55mIcelandair
Deal found 11/9C$ 847
Thu 18/96:30 a.m.LHR - SEA
2 stops15h 46mUnited Airlines
Sun 30/117:00 a.m.SEA - LHR
2 stops17h 30mUnited Airlines
Deal found 10/9C$ 848
Sun 5/109:25 p.m.LHR - SEA
1 stop31h 15mIcelandair
Mon 13/103:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Deal found 10/9C$ 849
Sun 19/107:25 a.m.LHR - SEA
1 stop17h 34mUnited Airlines
Sun 23/115:50 a.m.SEA - LHR
1 stop22h 00mUnited Airlines
Deal found 10/9C$ 854
Fri 10/106:55 a.m.LHR - SEA
1 stop18h 04mUnited Airlines
Mon 10/117:00 a.m.SEA - LHR
1 stop14h 55mUnited Airlines
Deal found 11/9C$ 855
Fri 10/106:30 a.m.LHR - SEA
1 stop13h 25mUnited Airlines
Sun 12/1012:43 p.m.SEA - LHR
1 stop12h 57mUnited Airlines
Deal found 8/9C$ 856
Wed 8/106:30 a.m.LHR - SEA
1 stop13h 20mDelta
Thu 16/108:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Deal found 9/9C$ 858
Fri 19/92:10 p.m.LHR - SEA
1 stop16h 06mUnited Airlines
Sat 4/107:00 a.m.SEA - LHR
1 stop15h 20mUnited Airlines
Deal found 10/9C$ 859
Sat 11/109:25 p.m.LHR - SEA
1 stop31h 15mIcelandair
Sat 18/103:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Deal found 9/9C$ 862
Sat 6/126:30 a.m.LHR - SEA
1 stop13h 40mUnited Airlines
Fri 26/1211:39 p.m.SEA - LHR
1 stop23h 01mUnited Airlines
Deal found 9/9C$ 863
Wed 17/99:55 a.m.LHR - SEA
1 stop14h 10mDelta
Tue 30/98:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Deal found 10/9C$ 865

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

Fly from

Heathrow

Fly to

Seattle

Route

Depart

Return

Price

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 7/10

1:05 p.m.-8:40 p.m.

1 stop15h 35m

Seattle/Tacoma Intl

Wed 12/11

2:35 p.m.-7:30 p.m.

1 stop20h 55m

C$ 847

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sun 19/10

7:25 a.m.-4:59 p.m.

1 stop17h 34m

Seattle/Tacoma Intl

Sun 23/11

5:50 a.m.-11:50 a.m.

1 stop22h 00m

C$ 854

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 10/10

6:55 a.m.-4:59 p.m.

1 stop18h 04m

Seattle/Tacoma Intl

Wed 12/11

6:20 a.m.-6:20 a.m.

1 stop16h 00m

C$ 855

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 3/11

6:30 a.m.-11:45 a.m.

1 stop13h 15m

Seattle/Tacoma Intl

Mon 17/11

4:48 p.m.-10:30 a.m.

Nonstop9h 42m

C$ 856

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 7/10

9:55 a.m.-4:05 p.m.

1 stop14h 10m

Seattle/Tacoma Intl

Mon 10/11

4:48 p.m.-10:30 a.m.

Nonstop9h 42m

C$ 865

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 7/10

9:55 a.m.-4:05 p.m.

1 stop14h 10m

Seattle/Tacoma Intl

Wed 12/11

4:48 p.m.-10:30 a.m.

Nonstop9h 42m

C$ 865

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 2/12

9:25 a.m.-11:30 a.m.

Nonstop10h 05m

Seattle/Tacoma Intl

Tue 9/12

1:28 p.m.-10:25 a.m.

1 stop12h 57m

C$ 866

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sun 21/9

4:15 p.m.-10:59 p.m.

1 stop14h 44m

Seattle/Tacoma Intl

Sat 4/10

1:57 p.m.-11:45 a.m.

1 stop13h 48m

C$ 867

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Sat 14/2

7:40 a.m.-6:09 p.m.

2 stops18h 29m

Seattle/Tacoma Intl

Fri 20/2

5:07 a.m.-5:55 a.m.

2 stops16h 48m

C$ 867

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Tue 4/11

6:20 a.m.-11:25 a.m.

1 stop13h 05m

Seattle/Tacoma Intl

Tue 10/3

8:20 p.m.-12:50 p.m.

Nonstop9h 30m

C$ 874

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/9

Showing 1-10 of 22 results
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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?

Use this chart to determine the optimal time to book a round-trip flight from Heathrow to Seattle. Price data was last updated on 29 August 2025.

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 62 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$ 262). Flying from London Heathrow Airport to Seattle in December is currently the most expensive (average of C$ 353). 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 11 September 2025.

When flying from London Heathrow Airport to Seattle, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 30% versus a flight in the morning.

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 17 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 10m. Icelandair provides one of the quickest options available for as low as C$ 865. 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 (93%), KLM (89%) or Air France (89%) 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$ 1,315, our data indicates the cheapest price to be C$ 936. The most popular route (London Heathrow - Seattle/Tacoma Intl), is priced around C$ 1,627.

  • 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$ 262). Flying from London Heathrow Airport to Seattle in December is currently the most expensive (average of C$ 353). 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
Leavenworth
SeaTac
Tukwila
Tacoma
Bothell
Cashmere
Renton
Olympia
Marysville
Lynnwood

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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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