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Cheap flights from Seattle to London Heathrow Airport from C$ 398

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 17/2. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
25 Jan — 1 Feb1
1 adult

The best prices from Seattle/Tacoma Intl to London Heathrow are usually found in November or February, booked 75 days in advance, depart on a Monday or Tuesday and return on a Wednesday

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 20 January 2025.

Round-trip from

C$ 854

One-way from

C$ 398

Popular in

June

Cheapest in

November

Average price

C$ 1,070
Icelandair
  • Icelandair
  • 16/4-25/4
  • 2 total stops
  • 24h 55m total
  • Seattle to London
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Icelandair
  • Icelandair
  • 17/2
  • 1 total stop
  • 20h 55m total
  • Seattle to London
Search Deals
High demand for flights, 21% potential price rise
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Best time to find cheap flights, 4% potential price drop
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Average for round-trip flights in January 2025
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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 20 January 2025.

Wed 16/43:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Thu 24/41:05 p.m.LHR - SEA
1 stop12h 45mIcelandair
Deal found 18/1C$ 854
Sun 16/37:50 p.m.SEA - LHR
Nonstop9h 25mIberia
Wed 26/31:50 p.m.LHR - SEA
1 stop16h 17mIberia
Deal found 20/1C$ 869
Wed 8/104:20 p.m.SEA - LHR
1 stop17h 20mScandinavian Airlines
Wed 22/107:05 a.m.LHR - SEA
2 stops14h 55mScandinavian Airlines
Deal found 20/1C$ 873
Sun 16/311:15 a.m.SEA - LHR
1 stop12h 35mKLM
Wed 26/36:30 a.m.LHR - SEA
1 stop13h 10mKLM
Deal found 20/1C$ 880
Wed 5/25:45 p.m.SEA - LHR
Nonstop9h 25mDelta
Wed 12/26:30 a.m.LHR - SEA
1 stop13h 16mDelta
Deal found 19/1C$ 884
Sun 2/26:50 p.m.SEA - LHR
Nonstop9h 25mFinnair
Tue 18/29:25 a.m.LHR - SEA
Nonstop9h 55mFinnair
Deal found 19/1C$ 890
Sun 6/410:35 a.m.SEA - LHR
2 stops17h 15mLufthansa
Thu 8/56:30 a.m.LHR - SEA
2 stops20h 03mLufthansa
Deal found 20/1C$ 916
Sun 16/33:05 p.m.SEA - LHR
1 stop12h 05mMultiple Airlines
Wed 26/38:55 a.m.LHR - SEA
2 stops19h 35mMultiple Airlines
Deal found 20/1C$ 926
Tue 4/37:05 p.m.SEA - LHR
1 stop31h 05mUnited Airlines
Tue 11/37:40 a.m.LHR - SEA
1 stop13h 40mUnited Airlines
Deal found 20/1C$ 929
Mon 24/37:50 p.m.SEA - LHR
Nonstop9h 25mBritish Airways
Thu 17/44:30 p.m.LHR - SEA
Nonstop9h 50mBritish Airways
Deal found 19/1C$ 951
Wed 5/312:37 p.m.SEA - LHR
2 stops43h 43mSWISS
Wed 12/36:40 p.m.LHR - SEA
2 stops35h 13mSWISS
Deal found 20/1C$ 971
Sat 18/1010:39 p.m.SEA - LHR
1 stop14h 06mJetBlue
Fri 24/1011:55 a.m.LHR - SEA
1 stop17h 34mJetBlue
Deal found 20/1C$ 1,010

Find flights from Seattle to Heathrow within your budget

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 20 January 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 16/4

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

1 stop12h 10m

London Heathrow

Fri 25/4

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

1 stop12h 45m

C$ 854

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 16/3

7:50 p.m.-12:15 p.m.

Nonstop9h 25m

London Heathrow

Wed 26/3

1:50 p.m.-11:07 p.m.

1 stop16h 17m

C$ 869

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 16/3

11:15 a.m.-6:50 a.m.

1 stop12h 35m

London Heathrow

Wed 26/3

6:30 a.m.-12:40 p.m.

1 stop13h 10m

C$ 880

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 5/2

1:40 p.m.-11:10 a.m.

1 stop13h 30m

London Heathrow

Wed 12/2

6:30 a.m.-11:46 a.m.

1 stop13h 16m

C$ 884

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 2/2

6:50 p.m.-12:15 p.m.

Nonstop9h 25m

London Heathrow

Tue 18/2

9:25 a.m.-11:20 a.m.

Nonstop9h 55m

C$ 890

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 16/3

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

1 stop12h 05m

London Heathrow

Wed 26/3

8:55 a.m.-9:30 p.m.

2 stops19h 35m

C$ 926

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 4/3

7:05 p.m.-10:10 a.m.

1 stop31h 05m

London Heathrow

Tue 11/3

7:40 a.m.-2:20 p.m.

1 stop13h 40m

C$ 929

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 25/3

10:35 a.m.-10:10 a.m.

1 stop16h 35m

London Heathrow

Thu 17/4

6:30 a.m.-12:25 p.m.

1 stop13h 55m

C$ 934

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 24/3

7:50 p.m.-12:15 p.m.

Nonstop9h 25m

London Heathrow

Thu 17/4

4:30 p.m.-6:20 p.m.

Nonstop9h 50m

C$ 951

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 5/3

12:37 p.m.-4:20 p.m.

2 stops43h 43m

London Heathrow

Wed 12/3

6:40 p.m.-10:53 p.m.

2 stops35h 13m

C$ 971

Flights are sorted by cheapest round-trip flights first.

Deals found on 20/1

Showing 1-10 of 31 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.

Travel insights for flights from Seattle to Heathrow

Get recent, data-driven insights about flights from Seattle to Heathrow including ideal travel times, pricing trends, and more.

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 17 January 2025.

The best time to book flights from Seattle to London Heathrow Airport is 75 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$ 874). 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 20 January 2025.

Unlike at noon, when flights are generally more expensive, you can save up to 13% 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 20 January 2025.

The most flights from SEA to LHR are scheduled on a Friday (22 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (6 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 20 January 2025.
To help decide which airline to fly from Seattle to London, see what other customers have to say about Iberia, KLM and Delta. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

China Airlines
8.2
Very good
737 reviews
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

Delta
8.0
Very good
8,521 reviews
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

Alaska Airlines
8.0
Very good
9,696 reviews
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

KLM
7.8
Good
1,341 reviews
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

Finnair
7.6
Good
1,285 reviews
China Airlines
8.2
Very good
737 reviews
Check prices

Crew

8.5

Boarding

8.3

Overall

8.2

Comfort

8.0

Entertainment

8.0

Food

7.8

Reviews

1 / 10

For the money it’s good value. Seat space rather small

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 13 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 7 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 Icelandair is currently your cheapest option to London Heathrow Airport, with prices starting at C$ 854. Additional round-trip tickets that might be worth considering are offered by Iberia and KLM, with the lowest prices starting at C$ 869 and C$ 880, respectively. Users have found that Icelandair is 29% 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$ 398 on Icelandair. Other airlines that offer cheap prices include WestJet from C$ 424 and Iberia from C$ 556 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: Singapore Airlines (85%), Aeromexico (85%), KLM (80%).

  • 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$ 1,814, our data shows the cheapest flight currently is C$ 593. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay C$ 866 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$ 874). 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?

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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 7 airlines flying from Seattle to Heathrow

Discover the top 7 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 20 January 2025.
AirlineCheapestAverageFlexibilityOn-time
IberiaCheapestC$ 638AverageC$ 946FlexibilityNo cancel feeOn-time77%
Search Iberia flights
IcelandairCheapestC$ 638AverageC$ 839FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Air FranceCheapestC$ 744AverageC$ 1,138FlexibilityNo cancel feeOn-time77%
Search Air France flights
KLMCheapestC$ 744AverageC$ 941FlexibilityNo cancel feeOn-time75%
Search KLM flights
Virgin AtlanticCheapestC$ 848AverageC$ 1,096FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
DeltaCheapestC$ 885AverageC$ 1,116FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
British AirwaysCheapestC$ 894AverageC$ 1,244FlexibilityNo 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?

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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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