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Cheap flights from Seattle to London Heathrow Airport from C$ 427

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 8/10. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
11 Oct — 18 Oct1
1 adult
1 adult, Economy

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

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 11 September 2025.

Round-trip from

C$ 703

One-way from

C$ 427

Popular in

June

Cheapest in

March

Average price

C$ 980

Good round-trip deal

C$ 957 or less

Good one-way deal

C$ 481 or less
United Airlines
  • United Airlines
  • 27/9-10/10
  • 2 total stops
  • 42h 34m total
  • Seattle to London
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WestJet
  • WestJet
  • 8/10
  • 1 total stop
  • 19h 25m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (C$ 316 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 52 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 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 11 September 2025.

Sat 27/911:10 p.m.SEA - LHR
1 stop24h 30mUnited Airlines
Fri 10/106:55 a.m.LHR - SEA
1 stop18h 04mUnited Airlines
Deal found 10/9C$ 703
Sun 21/93:15 p.m.SEA - LHR
1 stop14h 15mDelta
Tue 7/106:15 a.m.LHR - SEA
1 stop19h 25mDelta
Deal found 11/9C$ 704
Mon 6/101:12 p.m.SEA - LHR
1 stop13h 28mUnited Airlines
Wed 15/109:30 a.m.LHR - SEA
2 stops38h 15mUnited Airlines
Deal found 11/9C$ 705
Wed 8/108:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Thu 16/1011:30 a.m.LHR - SEA
1 stop14h 10mDelta
Deal found 11/9C$ 707
Tue 7/108:25 p.m.SEA - LHR
Nonstop9h 50mDelta
Tue 14/1011:45 a.m.LHR - SEA
1 stop32h 05mDelta
Deal found 11/9C$ 708
Wed 26/115:50 a.m.SEA - LHR
1 stop22h 00mUnited Airlines
Tue 2/1211:10 a.m.LHR - SEA
1 stop34h 10mUnited Airlines
Deal found 11/9C$ 711
Sat 4/109:55 p.m.SEA - LHR
1 stop24h 25mDelta
Thu 30/106:30 a.m.LHR - SEA
1 stop13h 15mDelta
Deal found 11/9C$ 714
Wed 8/105:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Tue 14/101:25 p.m.LHR - SEA
Nonstop10h 05mDelta
Deal found 11/9C$ 716
Tue 23/91:30 p.m.SEA - LHR
1 stop12h 20mMultiple Airlines
Tue 30/95:25 p.m.LHR - SEA
Nonstop10h 25mMultiple Airlines
Deal found 9/9C$ 722
Sat 4/109:58 p.m.SEA - LHR
1 stop24h 27mDelta
Fri 31/1012:20 p.m.LHR - SEA
Nonstop10h 25mDelta
Deal found 11/9C$ 723

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 11 September 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

Tue 30/9

8:25 p.m.-2:15 p.m.

Nonstop9h 50m

London Heathrow

Thu 9/10

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

1 stop13h 00m

C$ 705

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 2/11

5:00 a.m.-5:25 a.m.

1 stop16h 25m

London Heathrow

Tue 11/11

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

1 stop13h 05m

C$ 712

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 4/10

9:55 p.m.-6:20 a.m.

1 stop24h 25m

London Heathrow

Thu 30/10

6:30 a.m.-12:45 p.m.

1 stop13h 15m

C$ 714

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 7/1

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Fri 30/1

2:55 p.m.-4:55 p.m.

Nonstop10h 00m

C$ 716

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 25/2

6:50 p.m.-12:20 p.m.

Nonstop9h 30m

London Heathrow

Tue 3/3

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

Nonstop10h 05m

C$ 716

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 15/10

8:25 p.m.-2:15 p.m.

Nonstop9h 50m

London Heathrow

Fri 24/10

1:25 p.m.-3:30 p.m.

Nonstop10h 05m

C$ 716

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 6/10

1:30 p.m.-9:50 a.m.

1 stop12h 20m

London Heathrow

Tue 14/10

5:25 p.m.-7:50 p.m.

Nonstop10h 25m

C$ 723

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 2/10

7:00 p.m.-11:55 a.m.

1 stop32h 55m

London Heathrow

Tue 7/10

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

1 stop12h 45m

C$ 726

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 2/10

7:00 p.m.-11:55 a.m.

1 stop32h 55m

London Heathrow

Mon 6/10

9:25 p.m.-8:40 p.m.

1 stop31h 15m

C$ 728

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 30/10

8:00 p.m.-11:50 a.m.

1 stop32h 50m

London Heathrow

Tue 11/11

1:25 p.m.-10:45 p.m.

2 stops41h 20m

C$ 769

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/9

Showing 1-10 of 21 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 29 August 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$ 856). 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 11 September 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 28% on flights from Seattle to London Heathrow Airport by exploring options for tickets in the morning.

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 11 September 2025.
Read through reviews of airlines operating flights from Seattle to London Heathrow Airport, such as Virgin Atlantic,Icelandair, andIberia. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Virgin Atlantic
7.4
Good
664 reviews
Check prices

Entertainment

7.5

Food

6.9

Boarding

7.7

Comfort

7.3

Overall

7.4

Crew

8.1

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Virgin Atlantic
7.4
Good
664 reviews
Virgin Atlantic
7.4
Good
664 reviews
Check prices

Entertainment

7.5

Food

6.9

Boarding

7.7

Comfort

7.3

Overall

7.4

Crew

8.1

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Icelandair
7.0
Good
546 reviews
Virgin Atlantic
7.4
Good
664 reviews
Check prices

Entertainment

7.5

Food

6.9

Boarding

7.7

Comfort

7.3

Overall

7.4

Crew

8.1

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Iberia
7.0
Good
2,929 reviews
Virgin Atlantic
7.4
Good
664 reviews
Check prices

Entertainment

7.5

Food

6.9

Boarding

7.7

Comfort

7.3

Overall

7.4

Crew

8.1

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
British Airways
6.7
Okay
7,361 reviews
Virgin Atlantic
7.4
Good
664 reviews
Check prices

Entertainment

7.5

Food

6.9

Boarding

7.7

Comfort

7.3

Overall

7.4

Crew

8.1

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!

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 4 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.

  • How long is the flight from Seattle to London Heathrow Airport?

    There are many flights that can get you from Seattle to London Heathrow Airport in 9h 30m. Fly via Delta or Finnair to get the fastest option. Airlines will cover a distance of 7697 km. Generally, flights for this route are direct.

  • 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$ 577. Additional round-trip tickets that might be worth considering are offered by Virgin Atlantic and Iberia, with the lowest prices starting at C$ 699 and C$ 726, respectively. Users have found that Icelandair is 47% cheaper than the other options available to this destination.

  • 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: Aeromexico (88%), KLM (87%), Air France (87%).

  • 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$ 755, our data shows the cheapest flight currently is C$ 359. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay C$ 783 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$ 856). 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
Brentford
Sutton
Hounslow
Slough
Marlow
Leamington Spa
Milton Keynes
Romford
Watford
Bedford
Luton
Southall

Browse thousands of different options on Cheapflights for your next trip

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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 4 airlines flying from Seattle to Heathrow

Discover the top 4 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 11 September 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 577AverageC$ 764FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
Virgin AtlanticCheapestC$ 699AverageC$ 1,000FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
IberiaCheapestC$ 726AverageC$ 860FlexibilityNo cancel feeOn-time77%
Search Iberia flights
British AirwaysCheapestC$ 827AverageC$ 1,134FlexibilityNo 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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