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Cheap flights from Seattle to London Heathrow Airport from C$ 403

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 19/10. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
4 May — 11 May1
1 adult

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London Heathrow are usually found in March or November, booked 32 days in advance, depart on a Sunday or Tuesday and return on a Friday

Cheap flight deals from Seattle to Heathrow

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Heathrow (LHR). 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 29 April 2025.

Round-trip from

C$ 865

One-way from

C$ 403

Popular in

June

Cheapest in

March

Average price

C$ 978

Good round-trip deal

C$ 1,014 or less

Good one-way deal

C$ 560 or less
Scandinavian Airlines
  • Scandinavian Airlines
  • 10/9-19/9
  • 2 total stops
  • 48h 40m total
  • Seattle to London
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Icelandair
  • Icelandair
  • 19/10
  • 1 total stop
  • 12h 10m total
  • Seattle to London
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Highest demand for flights based on searches. 19% potential increase in price (C$ 390 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease (C$ 63 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 Seattle/Tacoma Intl to London Heathrow.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to London Heathrow.
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Find flight deals from Seattle to Heathrow

Cheapest flights from Seattle to Heathrow
Explore the most affordable flight options available from Seattle to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 29 April 2025.

Wed 10/94:00 p.m.SEA - LHR
1 stop33h 20mScandinavian Airlines
Fri 19/96:40 a.m.LHR - SEA
1 stop15h 20mScandinavian Airlines
Deal found 28/4C$ 865
Tue 23/93:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Tue 14/101:05 p.m.LHR - SEA
1 stop12h 45mIcelandair
Deal found 28/4C$ 895
Wed 3/97:20 a.m.SEA - LHR
1 stop15h 10mUnited Airlines
Wed 17/96:30 a.m.LHR - SEA
2 stops20h 06mUnited Airlines
Deal found 28/4C$ 938
Wed 27/87:20 a.m.SEA - LHR
1 stop18h 40mMultiple Airlines
Mon 15/98:05 p.m.LHR - SEA
2 stops30h 31mMultiple Airlines
Deal found 28/4C$ 948
Tue 23/98:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Tue 7/106:30 a.m.LHR - SEA
1 stop13h 20mDelta
Deal found 28/4C$ 955
Tue 23/910:00 a.m.SEA - LHR
2 stops17h 50mLufthansa
Tue 14/106:30 a.m.LHR - SEA
1 stop13h 25mLufthansa
Deal found 28/4C$ 956
Mon 1/94:25 p.m.SEA - LHR
1 stop17h 25mSWISS
Mon 8/98:05 p.m.LHR - SEA
2 stops30h 31mSWISS
Deal found 28/4C$ 976
Sun 17/81:30 p.m.SEA - LHR
Nonstop9h 20mBritish Airways
Tue 2/99:25 a.m.LHR - SEA
Nonstop9h 45mBritish Airways
Deal found 28/4C$ 1,013
Thu 10/711:25 p.m.SEA - LHR
1 stop13h 20mJetBlue
Fri 19/911:55 a.m.LHR - SEA
1 stop18h 17mJetBlue
Deal found 28/4C$ 1,059

Cheapflights Fare Finder

Customize your flight search to find flights from Seattle to Heathrow 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 29 April 2025.
Use the filters below to find and compare flights from Seattle to London Heathrow Airport that are best for you.

Fly from

Seattle

Fly to

Heathrow

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 10/9

4:00 p.m.-9:20 a.m.

1 stop33h 20m

London Heathrow

Fri 19/9

6:40 a.m.-2:00 p.m.

1 stop15h 20m

C$ 865

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 23/9

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

1 stop12h 10m

London Heathrow

Tue 14/10

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

1 stop12h 45m

C$ 895

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 3/9

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

1 stop15h 10m

London Heathrow

Wed 17/9

6:30 a.m.-6:36 p.m.

2 stops20h 06m

C$ 938

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 27/8

7:20 a.m.-10:00 a.m.

1 stop18h 40m

London Heathrow

Mon 15/9

8:05 p.m.-6:36 p.m.

2 stops30h 31m

C$ 948

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 23/9

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

Nonstop9h 45m

London Heathrow

Thu 2/10

6:30 a.m.-11:50 a.m.

1 stop13h 20m

C$ 955

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 13/8

10:00 a.m.-11:50 a.m.

2 stops17h 50m

London Heathrow

Thu 21/8

5:50 p.m.-4:59 p.m.

1 stop31h 09m

C$ 967

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/9

4:25 p.m.-5:50 p.m.

1 stop17h 25m

London Heathrow

Mon 8/9

8:05 p.m.-6:36 p.m.

2 stops30h 31m

C$ 976

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 17/8

1:30 p.m.-6:50 a.m.

Nonstop9h 20m

London Heathrow

Tue 2/9

9:25 a.m.-11:10 a.m.

Nonstop9h 45m

C$ 1,013

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 10/7

11:25 p.m.-8:45 p.m.

1 stop13h 20m

London Heathrow

Fri 19/9

11:55 a.m.-10:12 p.m.

1 stop18h 17m

C$ 1,059

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 19/10

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

1 stop12h 10m

C$ 403

Flights are sorted by cheapest round-trip flights first.

Deals found on 28/4

Showing 1-10 of 19 results
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Best time to book a flight from Seattle to Heathrow

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

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

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Heathrow. Price data was last updated on 25 April 2025.

The best time to book flights from Seattle to London Heathrow Airport is 32 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from Seattle to London Heathrow Airport?

Currently, January is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of C$ 560). Flying from Seattle to London Heathrow Airport in July is currently the most expensive (average of C$ 870). 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 SEA to LHR?

Find hourly flight availability from Seattle to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 29 April 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 29% on flights from Seattle to London Heathrow Airport by exploring options for tickets in the morning.

Weekly flight availability from Seattle to London Heathrow Airport

Explore weekly flight availability from Seattle to Heathrow. 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 29 April 2025.

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

Rainfall in Heathrow by month

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

In terms of precipitation, rainfall in London Heathrow Airport ranges from 40.0 - 70.0 mm per month. January is typically the wettest month, when rainfall can reach 70.0 mm. July is typically the driest time to visit London Heathrow Airport when rainfall is around 40.0 mm.

Temperature in Heathrow by month

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

If weather is an important factor for your trip to London Heathrow Airport, 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 17.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 4.0 C).

Reviews of airlines servicing Heathrow

Get insights into the airlines that provide service to Heathrow. 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 Heathrow. Reviews last updated 29 April 2025.
To help decide which airline to fly from Seattle to London, see what other customers have to say about Alaska Airlines, Delta and SWISS. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Alaska Airlines
8.0
Very good
9,961 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Delta
8.0
Very good
7,929 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
SWISS
7.5
Good
1,587 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
United Airlines
7.4
Good
8,696 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Virgin Atlantic
7.4
Good
642 reviews
Alaska Airlines
8.0
Very good
9,961 reviews
Check prices

Crew

8.5

Comfort

7.9

Overall

8.0

Boarding

8.2

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥

Related info for your journey

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

    Seattle/Tacoma Intl (SEA) is the airport you will fly out of if you book a flight from Seattle to London Heathrow. You should not have trouble finding flights to London Heathrow from Seattle/Tacoma Intl; the airport handles an average of 21 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 5 airlines have flights from the Seattle airport to London Heathrow. It is only a 18.4 km journey to Seattle/Tacoma Intl (SEA) from Seattle’s city centre.

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

    Flying on Scandinavian Airlines is currently your cheapest option to London Heathrow Airport, with prices starting at C$ 865. Additional round-trip tickets that might be worth considering are offered by Icelandair and United Airlines, with the lowest prices starting at C$ 895 and C$ 938, respectively. Users have found that Scandinavian Airlines is 23% cheaper than the other options available to this destination.

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

    One-way options have recently been found by users for as low as C$ 403 on Icelandair. Other airlines that offer cheap prices include WestJet from C$ 557 and Delta from C$ 579 one-way.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Seattle to London Heathrow Airport on time: Scandinavian Airlines (90%), KLM (85%), Aeromexico (85%).

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

    While on average a flight from Seattle to London Heathrow Airport is generally C$ 3,081, our data shows the cheapest flight currently is C$ 428. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay C$ 1,067 for that flight.

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

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

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

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

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

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

    Currently, January is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of C$ 560). Flying from Seattle to London Heathrow Airport in July is currently the most expensive (average of C$ 870). 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
Brentford
Hounslow
Sutton
Slough
Milton Keynes
Romford
Watford
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Alternative routes for Seattle to Heathrow

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Gatwick flights

Top 6 airlines flying from Seattle to Heathrow

Discover the top 6 airlines that operate flights from Seattle to Heathrow. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 29 April 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 611AverageC$ 800FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
IberiaCheapestC$ 632AverageC$ 847FlexibilityNo cancel feeOn-time77%
Search Iberia flights
Virgin AtlanticCheapestC$ 795AverageC$ 1,010FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
KLMCheapestC$ 809AverageC$ 946FlexibilityNo cancel feeOn-time75%
Search KLM flights
Air FranceCheapestC$ 856AverageC$ 1,089FlexibilityNo cancel feeOn-time77%
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British AirwaysCheapestC$ 856AverageC$ 1,166FlexibilityNo cancel feeOn-time70%
Search British Airways flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Seattle to Heathrow?

900+ travel sites are searched through when a user searches for a flight using Cheapflights. From the search interface, users can use filters to choose airlines, airports, flight times, cabin classes and more to their preference. Book your flight to Heathrow from Seattle today with Cheapflights!

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

Millions of users choose and trust Cheapflights to book the best flight deals from Seattle to Heathrow for free. We help you search and compare prices from hundreds of airlines for the right flight just for you.

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

Users can book flights with no change fees policies with our dedicated filters. Book flights from Seattle to Heathrow flexibly with Cheapflights today.

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

Yes, Cheapflights offers price alerts on Seattle to Heathrow flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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