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Cheap flights from Seattle to London Heathrow Airport from £268

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 6/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LHR
14 dic — 21 dic1
1 adult
1 adult, Economy, 0 bags

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London Heathrow are usually found in October or March, booked 65 days in advance, depart on a Tuesday or Thursday 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 14 novembre 2025.

Round-trip from

£401

One-way from

£268

Popular in

June

Cheapest in

October

Average price

£546

Good round-trip deal

£495 or less

Good one-way deal

£467 or less
Icelandair
  • Icelandair
  • 27/3-14/4
  • 2 total stops
  • 48h 50m total
  • Seattle to London
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WestJet
  • WestJet
  • 6/5
  • 1 total stop
  • 14h 00m total
  • Seattle to London
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Highest demand for flights based on searches. 17% potential increase in price (£99 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£16 potential savings vs. average return price).
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Average for round-trip flights in November 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

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 14 novembre 2025.

dom 30/1114:35SEA - LHR
1 stop12h 15mIcelandair
mer 10/1212:15LHR - SEA
1 stop12h 45mIcelandair
Deal found 11/11£406
mar 25/1114:35SEA - LHR
1 stop20h 55mIcelandair
mar 16/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 12/11£413
mar 18/1114:35SEA - LHR
1 stop20h 55mIcelandair
sab 28/220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 13/11£413
mer 26/1114:35SEA - LHR
1 stop20h 55mIcelandair
mar 2/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 13/11£414
mar 25/1114:35SEA - LHR
1 stop12h 15mIcelandair
mar 2/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 10/11£416
mer 3/1220:05SEA - LHR
1 stop11h 30mAer Lingus
ven 12/1212:10LHR - SEA
1 stop14h 10mAer Lingus
Deal found 11/11£419
lun 1/1220:05SEA - LHR
1 stop12h 45mAer Lingus
ven 5/1208:50LHR - SEA
1 stop17h 30mAer Lingus
Deal found 11/11£421
mer 12/1120:05SEA - LHR
1 stop11h 30mAer Lingus
mer 26/1112:10LHR - SEA
1 stop14h 10mAer Lingus
Deal found 11/11£423
mer 12/1120:05SEA - LHR
1 stop11h 30mAer Lingus
mer 19/1107:50LHR - SEA
1 stop18h 30mAer Lingus
Deal found 11/11£423
mer 19/1115:40SEA - LHR
1 stop12h 10mLufthansa
mer 26/1106:35LHR - SEA
1 stop14h 45mLufthansa
Deal found 10/11£424
mar 18/1114:35SEA - LHR
1 stop12h 15mIcelandair
mer 3/1220:35LHR - SEA
1 stop28h 25mIcelandair
Deal found 11/11£426

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 14 novembre 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

mar 25/11

16:48-10:30

Nonstop9h 42m

London Heathrow

mar 2/12

11:45-11:50

1 stop32h 05m

£438

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

dom 23/11

23:55-07:05

1 stop23h 10m

London Heathrow

mar 9/12

06:20-11:25

1 stop13h 05m

£438

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

lun 1/12

19:20-12:50

Nonstop9h 30m

London Heathrow

lun 8/12

11:45-11:50

1 stop32h 05m

£438

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mar 2/12

16:48-10:30

Nonstop9h 42m

London Heathrow

gio 11/12

06:30-11:50

1 stop13h 20m

£438

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mar 2/12

18:50-12:20

Nonstop9h 30m

London Heathrow

ven 12/12

09:25-11:30

Nonstop10h 05m

£442

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mer 18/2

16:55-10:30

Nonstop9h 35m

London Heathrow

ven 27/2

06:20-13:20

1 stop15h 00m

£442

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

lun 8/12

16:48-10:30

Nonstop9h 42m

London Heathrow

mar 16/12

08:55-17:47

1 stop16h 52m

£450

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

dom 11/1

11:55-12:50

2 stops40h 55m

£292

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

lun 12/1

15:40-11:50

1 stop12h 10m

£296

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

mar 10/2

15:40-11:50

1 stop12h 10m

£299

Flights are sorted by cheapest return flights first.

Deals found on 12/11

Showing 1-10 of 18 results
1
2

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 7 November 2025.

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 65 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 £378). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of £601). 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 14 novembre 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 42% on flights from Seattle to London Heathrow Airport by exploring options for tickets at midday.

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 14 novembre 2025.
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
673 reviews
Check prices

Comfort

7.3

Overall

7.5

Crew

8.1

Boarding

7.7

Food

6.9

Entertainment

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
673 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Comfort

7.3

Overall

7.5

Crew

8.1

Boarding

7.7

Food

6.9

Entertainment

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
7,521 reviews
Virgin Atlantic
7.5
Good
673 reviews
Check prices

Comfort

7.3

Overall

7.5

Crew

8.1

Boarding

7.7

Food

6.9

Entertainment

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 11 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 £438, Delta can have you in London Heathrow Airport from Seattle in 9h 42m. 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 £360. Another airline that can offer you cheap pricing is Virgin Atlantic. You may be able to fly from Seattle to London Heathrow Airport for 40% 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 £292 on WestJet. Other airlines that offer cheap prices include Lufthansa from £296 and United Airlines from £299 one-way.

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

    Consider KLM (89%), Air France (84%) or Delta (84%) 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 £529, our data shows the cheapest flight currently is £391. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay £361 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 £378). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of £601). 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
Slough
Gatwick
Hounslow
Northampton
Luton
Ilford
Wembley
Deal
Hayes
Colchester
Watford
Winchester
Swindon
Crawley
Brentford
Romford
Chichester
Ipswich

Browse thousands of different options on Cheapflights for your next trip

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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 14 novembre 2025.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapest£360Average£605FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Virgin AtlanticCheapest£375Average£626FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic 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?

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.

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