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Cheap flights from Seattle to London Heathrow Airport from C$ 412

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 21/9. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
22 Apr — 29 Apr1
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 17 April 2025.

Round-trip from

C$ 887

One-way from

C$ 412

Popular in

June

Cheapest in

March

Average price

C$ 975

Good round-trip deal

C$ 1,014 or less

Good one-way deal

C$ 561 or less
Icelandair
  • Icelandair
  • 1/10-13/10
  • 2 total stops
  • 40h 35m total
  • Seattle to London
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Icelandair
  • Icelandair
  • 21/9
  • 1 total stop
  • 20h 35m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 20% potential increase in price (C$ 407 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease (C$ 66 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 17 April 2025.

Wed 1/103:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Mon 13/109:25 p.m.LHR - SEA
1 stop28h 25mIcelandair
Deal found 17/4C$ 887
Fri 23/54:00 p.m.SEA - LHR
2 stops32h 55mScandinavian Airlines
Mon 26/57:05 a.m.LHR - SEA
2 stops14h 45mScandinavian Airlines
Deal found 17/4C$ 911
Mon 1/97:15 p.m.SEA - LHR
1 stop34h 05mUnited Airlines
Tue 30/96:30 a.m.LHR - SEA
2 stops15h 46mUnited Airlines
Deal found 16/4C$ 936
Mon 8/97:20 a.m.SEA - LHR
1 stop18h 40mMultiple Airlines
Mon 29/96:40 p.m.LHR - SEA
2 stops31h 56mMultiple Airlines
Deal found 16/4C$ 947
Mon 1/910:00 a.m.SEA - LHR
2 stops17h 50mLufthansa
Wed 1/1010:50 a.m.LHR - SEA
1 stop14h 09mLufthansa
Deal found 16/4C$ 951
Wed 10/95:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Thu 18/96:30 a.m.LHR - SEA
1 stop13h 15mDelta
Deal found 16/4C$ 953
Fri 2/59:23 p.m.SEA - LHR
1 stop15h 22mJetBlue
Fri 16/58:15 a.m.LHR - SEA
1 stop20h 39mJetBlue
Deal found 17/4C$ 966
Mon 1/94:25 p.m.SEA - LHR
1 stop18h 55mSWISS
Mon 15/96:40 p.m.LHR - SEA
2 stops31h 56mSWISS
Deal found 17/4C$ 975
Sun 7/91:30 p.m.SEA - LHR
Nonstop9h 20mBritish Airways
Wed 17/99:50 a.m.LHR - SEA
Nonstop9h 45mBritish Airways
Deal found 16/4C$ 1,011
Mon 4/88:20 p.m.SEA - LHR
Nonstop9h 20mFinnair
Thu 14/810:20 a.m.LHR - SEA
1 stop13h 40mFinnair
Deal found 17/4C$ 1,075
Wed 30/77:10 p.m.SEA - LHR
1 stop19h 15mTurkish Airlines
Wed 6/86:30 a.m.LHR - SEA
1 stop36h 05mTurkish Airlines
Deal found 17/4C$ 1,138
Thu 15/55:35 p.m.SEA - LHR
Nonstop9h 45mVirgin Atlantic
Thu 22/59:55 a.m.LHR - SEA
1 stop14h 02mVirgin Atlantic
Deal found 17/4C$ 1,195

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 17 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 1/10

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

1 stop12h 10m

London Heathrow

Mon 13/10

9:25 p.m.-5:50 p.m.

1 stop28h 25m

C$ 887

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 23/5

4:00 p.m.-8:55 a.m.

2 stops32h 55m

London Heathrow

Mon 26/5

7:05 a.m.-1:50 p.m.

2 stops14h 45m

C$ 911

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/9

7:15 p.m.-1:20 p.m.

1 stop34h 05m

London Heathrow

Tue 30/9

6:30 a.m.-2:16 p.m.

2 stops15h 46m

C$ 936

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 8/9

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

1 stop18h 40m

London Heathrow

Mon 29/9

6:40 p.m.-6:36 p.m.

2 stops31h 56m

C$ 947

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/9

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

2 stops17h 50m

London Heathrow

Wed 1/10

10:50 a.m.-4:59 p.m.

1 stop14h 09m

C$ 951

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 10/9

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

Nonstop9h 45m

London Heathrow

Thu 18/9

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

1 stop13h 15m

C$ 953

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 2/5

9:23 p.m.-8:45 p.m.

1 stop15h 22m

London Heathrow

Fri 16/5

8:15 a.m.-8:54 p.m.

1 stop20h 39m

C$ 966

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/9

4:25 p.m.-7:20 p.m.

1 stop18h 55m

London Heathrow

Mon 15/9

6:40 p.m.-6:36 p.m.

2 stops31h 56m

C$ 975

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 7/9

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

Nonstop9h 20m

London Heathrow

Wed 17/9

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

Nonstop9h 45m

C$ 1,011

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 4/8

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

Nonstop9h 20m

London Heathrow

Thu 14/8

10:20 a.m.-4:00 p.m.

1 stop13h 40m

C$ 1,075

Flights are sorted by cheapest round-trip flights first.

Deals found on 17/4

Showing 1-10 of 25 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 11 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$ 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 17 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 17 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 17 April 2025.
To help decide which airline to fly from Seattle to London, see what other customers have to say about China Airlines, Delta and Alaska Airlines. 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
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver
China Airlines
8.2
Very good
729 reviews
China Airlines
8.2
Very good
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver
Delta
8.0
Very good
7,916 reviews
China Airlines
8.2
Very good
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver
Alaska Airlines
8.0
Very good
9,887 reviews
China Airlines
8.2
Very good
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver
Finnair
7.6
Good
1,269 reviews
China Airlines
8.2
Very good
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver
SWISS
7.5
Good
1,580 reviews
China Airlines
8.2
Very good
729 reviews
Check prices

Comfort

8.0

Boarding

8.3

Crew

8.5

Food

7.8

Entertainment

8.0

Overall

8.2

Reviews

1 / 20
6.0
Good

Anonymous,Apr 2025

YVR - TPE

I like the system, but the problem is the food , thre is no option, as a chef i don't recommend the food is worst we keep our hungry until taipe from vancouver

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 20 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 6 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$ 887. Additional round-trip tickets that might be worth considering are offered by Scandinavian Airlines and United Airlines, with the lowest prices starting at C$ 911 and C$ 936, respectively. Users have found that Icelandair is 22% 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$ 412 on Icelandair. Other airlines that offer cheap prices include Lufthansa from C$ 580 and United Airlines from C$ 586 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$ 3,065, our data shows the cheapest flight currently is C$ 406. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay C$ 980 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?

Book flights to Seattle if you plan to visit one of these locations
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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 17 April 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 611AverageC$ 803FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
IberiaCheapestC$ 633AverageC$ 848FlexibilityNo cancel feeOn-time77%
Search Iberia flights
Virgin AtlanticCheapestC$ 795AverageC$ 1,011FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
KLMCheapestC$ 809AverageC$ 947FlexibilityNo cancel feeOn-time75%
Search KLM flights
Air FranceCheapestC$ 857AverageC$ 1,090FlexibilityNo cancel feeOn-time77%
Search Air France flights
British AirwaysCheapestC$ 857AverageC$ 1,167FlexibilityNo cancel feeOn-time70%
Search British Airways flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

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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