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Cheap flights from London Heathrow Airport to Seattle from C$ 736

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 6/5. Fares are subject to change and may not be available on all flights or dates of travel.
LHR — SEA
20 Apr — 27 Apr1
1 adult

Cheapflights Tip: The best prices from London Heathrow to Seattle/Tacoma Intl are usually found in February or November, booked 54 days in advance, depart on a Friday 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 15 April 2025.

Round-trip from

C$ 836

One-way from

C$ 736

Popular in

July

Cheapest in

February

Average price

C$ 1,007

Good round-trip deal

C$ 1,051 or less
United Airlines
  • United Airlines
  • 11/5-18/5
  • 2 total stops
  • 31h 09m total
  • London to Seattle
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WestJet
  • WestJet
  • 6/5
  • 1 total stop
  • 30h 48m total
  • London to Seattle
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Highest demand for flights based on searches. 15% potential increase in price (C$ 276 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 37 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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Price to beat on a round-trip 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 15 April 2025.

Sun 11/59:00 a.m.LHR - SEA
1 stop15h 59mUnited Airlines
Sun 18/57:20 a.m.SEA - LHR
1 stop15h 10mUnited Airlines
Deal found 13/4C$ 836
Fri 19/96:00 a.m.LHR - SEA
2 stops20h 36mSWISS
Mon 22/92:29 p.m.SEA - LHR
2 stops20h 51mSWISS
Deal found 14/4C$ 845
Thu 11/96:30 a.m.LHR - SEA
1 stop13h 25mLufthansa
Sat 27/91:09 p.m.SEA - LHR
1 stop13h 31mLufthansa
Deal found 14/4C$ 853
Fri 19/91:05 p.m.LHR - SEA
1 stop12h 45mIcelandair
Sun 21/93:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Deal found 15/4C$ 856
Wed 30/49:55 a.m.LHR - SEA
1 stop14h 05mDelta
Tue 13/55:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Deal found 14/4C$ 889
Mon 21/48:50 a.m.LHR - SEA
1 stop16h 09mBritish Airways
Mon 28/46:45 p.m.SEA - LHR
1 stop12h 10mBritish Airways
Deal found 14/4C$ 892
Wed 30/45:25 p.m.LHR - SEA
Nonstop10h 20mKLM
Wed 7/58:20 p.m.SEA - LHR
Nonstop9h 55mKLM
Deal found 15/4C$ 906
Mon 3/116:00 a.m.LHR - SEA
2 stops22h 10mAustrian Airlines
Wed 26/117:00 a.m.SEA - LHR
1 stop14h 55mAustrian Airlines
Deal found 15/4C$ 954
Wed 3/99:50 a.m.LHR - SEA
Nonstop9h 45mFinnair
Tue 16/99:44 a.m.SEA - LHR
1 stop17h 06mFinnair
Deal found 14/4C$ 968
Mon 16/68:40 a.m.LHR - SEA
1 stop14h 15mMultiple Airlines
Sun 22/67:00 a.m.SEA - LHR
1 stop15h 20mMultiple Airlines
Deal found 14/4C$ 975
Tue 30/97:30 p.m.LHR - SEA
1 stop26h 30mScandinavian Airlines
Wed 15/104:20 p.m.SEA - LHR
1 stop15h 40mScandinavian Airlines
Deal found 14/4C$ 976

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 15 April 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

Sun 11/5

9:00 a.m.-4:59 p.m.

1 stop15h 59m

Seattle/Tacoma Intl

Sun 18/5

7:20 a.m.-6:30 a.m.

1 stop15h 10m

C$ 836

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 19/9

6:00 a.m.-6:36 p.m.

2 stops20h 36m

Seattle/Tacoma Intl

Mon 22/9

2:29 p.m.-7:20 p.m.

2 stops20h 51m

C$ 845

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Thu 11/9

6:30 a.m.-11:55 a.m.

1 stop13h 25m

Seattle/Tacoma Intl

Sat 27/9

1:09 p.m.-10:40 a.m.

1 stop13h 31m

C$ 853

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Fri 19/9

1:05 p.m.-5:50 p.m.

1 stop12h 45m

Seattle/Tacoma Intl

Sun 21/9

3:45 p.m.-11:55 a.m.

1 stop12h 10m

C$ 856

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Wed 30/4

10:30 a.m.-4:59 p.m.

1 stop14h 29m

Seattle/Tacoma Intl

Wed 7/5

8:20 p.m.-1:40 p.m.

Nonstop9h 20m

C$ 878

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Wed 30/4

9:55 a.m.-4:00 p.m.

1 stop14h 05m

Seattle/Tacoma Intl

Tue 13/5

5:35 p.m.-11:20 a.m.

Nonstop9h 45m

C$ 889

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 8/9

12:15 p.m.-8:42 p.m.

1 stop16h 27m

Seattle/Tacoma Intl

Mon 29/9

7:00 a.m.-9:40 a.m.

2 stops18h 40m

C$ 899

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Wed 30/4

5:25 p.m.-7:45 p.m.

Nonstop10h 20m

Seattle/Tacoma Intl

Wed 7/5

8:20 p.m.-2:15 p.m.

Nonstop9h 55m

C$ 906

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Wed 3/9

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

Nonstop9h 45m

Seattle/Tacoma Intl

Tue 16/9

9:44 a.m.-10:50 a.m.

1 stop17h 06m

C$ 968

LondonSeattle

LHR - SEA

LHRSEA

London Heathrow

Mon 16/6

8:40 a.m.-2:55 p.m.

1 stop14h 15m

Seattle/Tacoma Intl

Sun 22/6

7:00 a.m.-6:20 a.m.

1 stop15h 20m

C$ 975

Flights are sorted by cheapest round-trip flights first.

Deals found on 14/4

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 11 April 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 54 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$ 261). 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 15 April 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 at noon, which can drop the price by up to 12% versus a flight in the morning.

Weekly flight availability from London Heathrow Airport to Seattle

Explore weekly flight availability from Heathrow to Seattle. 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 15 April 2025.

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

Rainfall in Seattle by month

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

In terms of precipitation, rainfall in Seattle ranges from 18.0 - 168.0 mm per month. November is typically the wettest month, when rainfall can reach 168.0 mm. July is typically the driest time to visit Seattle when rainfall is around 18.0 mm.

Temperature in Seattle by month

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

If weather is an important factor for your trip to Seattle, 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 19.0 C. Travellers hoping to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 5.0 C).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated 15 April 2025.
See what other customers who have flown with Delta, KLM and Finnair from London to Seattle have to say. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
Delta
8.0
Very good
7,917 reviews
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
KLM
7.8
Good
1,323 reviews
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
Finnair
7.6
Good
1,269 reviews
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
Austrian Airlines
7.6
Good
775 reviews
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
SWISS
7.5
Good
1,578 reviews
Delta
8.0
Very good
7,917 reviews
Check prices

Crew

8.5

Boarding

8.2

Overall

8.0

Comfort

7.9

Entertainment

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

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.

  • What are the cheapest airlines flying from London Heathrow Airport to Seattle round-trip?

    Currently priced at C$ 836, United Airlines will fly you from London Heathrow Airport to Seattle and back. In addition to United Airlines, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from SWISS and Lufthansa - these airlines can fly you to your destination from C$ 845 and C$ 853, respectively. These flights start at 23% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from London Heathrow Airport to Seattle one-way?

    The cheapest airlines for a one-way flight from London Heathrow Airport to Seattle are WestJet (C$ 736), Aer Lingus (C$ 756), and Icelandair (C$ 969).

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

    Consider Singapore Airlines (96%), Aeromexico (91%) or KLM (91%) 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$ 1,361, our data indicates the cheapest price to be C$ 1,029. The most popular route (London Heathrow - Seattle/Tacoma Intl), is priced around C$ 1,763.

  • 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$ 261). 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 London Heathrow Airport?

Book flights to London Heathrow Airport if you plan to visit one of these locations
SeaTac
Tukwila
Marysville
Bothell
Leavenworth
Tacoma
Olympia
Lynnwood

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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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