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Cheap flights from Seattle to London Heathrow Airport from £275

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 9/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
17 Mar — 24 Mar1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London Heathrow are usually found in January or October, booked 83 days in advance, depart on a Tuesday or Thursday and return on a Wednesday

Cheap flight deals from Seattle to Heathrow

Enter your travel dates to find the best prices.

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 15 February 2026.

Fri 24/419:00
SEA
-
LHR
1 stop17h 20m
Icelandair
Mon 4/521:25
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 11/2£397
Sun 4/1019:00
SEA
-
LHR
1 stop32h 55m
Icelandair
Mon 12/1021:25
LHR
-
SEA
1 stop28h 30m
Icelandair
Deal found 12/2£398
Sat 3/1015:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Sat 24/1021:25
LHR
-
SEA
1 stop31h 20m
Icelandair
Deal found 12/2£398
Sun 19/415:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Tue 28/413:05
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 11/2£399
Wed 22/419:00
SEA
-
LHR
1 stop17h 20m
Icelandair
Mon 27/421:25
LHR
-
SEA
1 stop31h 15m
Icelandair
Deal found 10/2£400
Mon 6/419:00
SEA
-
LHR
1 stop32h 55m
Icelandair
Thu 23/413:05
LHR
-
SEA
1 stop15h 35m
Icelandair
Deal found 13/2£400
Sun 1/315:40
SEA
-
LHR
1 stop12h 10m
Air Canada
Thu 12/314:30
LHR
-
SEA
1 stop15h 27m
Air Canada
Deal found 10/2£401
Thu 26/214:35
SEA
-
LHR
1 stop12h 15m
Icelandair
Thu 5/320:35
LHR
-
SEA
1 stop28h 25m
Icelandair
Deal found 11/2£402
Wed 29/419:00
SEA
-
LHR
1 stop17h 20m
Icelandair
Mon 11/513:05
LHR
-
SEA
1 stop12h 50m
Icelandair
Deal found 13/2£403
Tue 3/314:35
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 18/312:15
LHR
-
SEA
1 stop12h 45m
Icelandair
Deal found 13/2£403
Fri 27/214:35
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 4/320:35
LHR
-
SEA
1 stop28h 25m
Icelandair
Deal found 12/2£404
Mon 20/415:40
SEA
-
LHR
1 stop12h 15m
Icelandair
Wed 6/513:05
LHR
-
SEA
1 stop15h 35m
Icelandair
Deal found 13/2£405

Find 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 15 February 2026.

Round-trip from

£397

One-way from

£275

Popular in

June

Cheapest in

January

Average price

£508

Good round-trip deal

£452 or less

Good one-way deal

£302 or less
Icelandair
  • Icelandair
  • 24/4-4/5
  • 2 total stops
  • 45h 50m total
  • Seattle to London
Search Deals
8/4
  • 8/4
  • 2 total stops
  • 42h 35m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (£90 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£14 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 2026
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to London Heathrow.
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to London Heathrow.
Search Deals

Cheapflights Fare Finder

 
Customise 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 858,174 searches. Data last updated 15 February 2026.
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 14/4

15:35-13:05

1 stop13h 30m

London Heathrow

Tue 21/4

06:30-11:45

1 stop13h 15m

£464

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 5/5

21:45-15:35

Nonstop9h 50m

London Heathrow

Tue 19/5

06:30-11:42

1 stop13h 12m

£464

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 29/4

21:45-15:35

Nonstop9h 50m

London Heathrow

Mon 11/5

08:40-11:42

1 stop35h 02m

£465

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 22/4

18:20-12:10

Nonstop9h 50m

London Heathrow

Thu 30/4

06:30-11:45

1 stop13h 15m

£465

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 24/3

17:40-10:30

Nonstop9h 50m

London Heathrow

Thu 2/4

09:55-16:30

1 stop14h 35m

£465

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 13/4

21:45-15:35

Nonstop9h 50m

London Heathrow

Wed 22/4

11:30-17:38

1 stop14h 08m

£469

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 12/3

07:15-07:25

1 stop17h 10m

London Heathrow

Thu 26/3

11:10-22:16

1 stop18h 06m

£483

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 1/4

15:30-13:05

1 stop13h 35m

London Heathrow

Wed 8/4

17:45-20:04

Nonstop10h 19m

£483

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 29/4

13:35-06:50

Nonstop9h 15m

London Heathrow

Fri 15/5

09:50-11:35

Nonstop9h 45m

£485

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 13/5

18:20-12:10

Nonstop9h 50m

London Heathrow

Wed 20/5

11:40-14:00

Nonstop10h 20m

£485

Flights are sorted by cheapest return flights first.

Deals found on 11/2

Showing 1-10 of 22 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 return 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 return flight from Seattle to Heathrow. Price data was last updated on 6 February 2026.

The price you pay for your flight from Seattle to London Heathrow Airport may vary depending on when you book. For the best chance of a lower fare, look to book 83 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 Seattle to London Heathrow Airport?

Currently, October is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of £362). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of £564). 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 15 February 2026.

When flying from Seattle to London Heathrow Airport, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

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 15 February 2026.
Read through reviews of airlines operating flights from Seattle to London Heathrow Airport, such as Virgin Atlantic and British Airways. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Comfort

7.3

Entertainment

7.6

Boarding

7.7

Crew

8.2

Food

6.9

Overall

7.5

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
7.5
Good
678 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Comfort

7.3

Entertainment

7.6

Boarding

7.7

Crew

8.2

Food

6.9

Overall

7.5

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
7,741 reviews
Virgin Atlantic
7.5
Good
678 reviews
Check prices

Comfort

7.3

Entertainment

7.6

Boarding

7.7

Crew

8.2

Food

6.9

Overall

7.5

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?

    If you book a flight to London Heathrow from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There are 15 flights from Seattle/Tacoma Intl to London Heathrow per day from 2 different airlines.

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

    For as low as £481, KLM can have you in London Heathrow Airport from Seattle in 9h 30m. The distance from Seattle to London Heathrow Airport is about 4783 mi. All flights are typically direct.

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

    Cheapflights users have booked flights from Seattle to London Heathrow Airport round-trip from £347. Another airline that can offer you cheap pricing is Virgin Atlantic. You may be able to fly from Seattle to London Heathrow Airport for 38% less than the average price by searching for these airlines.

  • 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 £158 on Icelandair. Other airlines that offer cheap prices include British Airways from £288 and Virgin Atlantic from £289 one-way.

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

    Consider American Airlines (78%), Alaska Airlines (78%) or Aer Lingus (78%) when booking your flight. These represent the most reliable airlines when flying from Seattle to London Heathrow Airport.

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

    While on average a flight from Seattle to London Heathrow Airport is generally £445, our data shows the cheapest flight currently is £174. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay £387 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 holiday 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, October is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of £362). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of £564). 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
Milton Keynes
Croydon
Luton
Wembley
Northampton
Gatwick
Slough
Hounslow
Ilford
Hayes
Brentford
Colchester
Watford
Guildford
Chelmsford
Eastbourne
Crawley
Kingston upon Thames
Ipswich
Swindon

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 2 airlines flying from Seattle to Heathrow

Discover the top 2 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 858,174 searches. Data last updated 15 February 2026.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapest£347Average£510FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£362Average£576FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers 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?

Cheapflights helps you search for flights from Seattle to Heathrow via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

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

Cheapflights helps you find that perfect flight to Heathrow from Seattle by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

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

Yes! Cheapflights helps users easily find flights from Seattle to Heathrow with no change fees.

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

Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!

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