What day of the week experiences the fewest flight delays on this route?

Tuesday tends to have the lowest number of delays on this route, whereas Sunday has historically faced a higher average of delays compared to other days of the week.

How often are flights from Seattle to London delayed?

About 16% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 123 minutes.

Which airport typically offers the quickest layover for flights from Seattle to London Heathrow Airport?

Flights via Reykjavik (KEF) offer the fastest connection on this route, with an average layover time of 1h 51m.

What’s the cheapest layover airport for flights from Seattle to London Heathrow Airport?

Montreal (YUL) is the most affordable 1-stop option, with an average round-trip price of $631.

What’s the top layover airport for flights from Seattle to London Heathrow Airport?

Reykjavik (KEF) – chosen by Cheapflights users on 71% of 1-stop itineraries from Seattle to London Heathrow Airport on Cheapflights.

What’s the fastest layover option from Seattle to London Heathrow Airport?

Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 12h 10m.

Which airline has the best punctuality record on Seattle to London flights?

Over the last year, Virgin Atlantic have had the lowest number of delays on this route, with just 6% of flights being delayed.

What is the most punctual flight time for Seattle to London flights?

Historically, flights departing in the early afternoon are less likely to be delayed, whereas flights leaving at night tend to experience delays more often.

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

For as low as $615, KLM can have you in London Heathrow Airport from Seattle in 9h 30m. The distance between Seattle and London Heathrow Airport is about 4783 mi. All flights are typically nonstop.

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

Our cheapest airline available from Seattle to London Heathrow Airport is Scandinavian Airlines. Our recent data shows that you can find tickets from as low as $465 on this airline. Additional options worth looking into are Icelandair and Aer Lingus, starting at $480 and $500 round-trip. Scandinavian Airlines is currently priced 41% below the average price you’ll pay for this route.

What are the cheapest airlines to fly from Seattle to London Heathrow Airport one-way?

The cheapest airlines for a one-way flight from Seattle to London Heathrow Airport are Icelandair ($166), WestJet ($222), and Aer Lingus ($362).

Weekly flight availability from Seattle to London Heathrow Airport

The most flights from SEA to LHR are scheduled on a Tuesday (21 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (11 on average).

In terms of precipitation, rainfall in London Heathrow Airport ranges from 1.6 - 2.8 inches per month. January is typically the wettest month, when rainfall can reach 2.8 in. July is typically the driest time to visit London Heathrow Airport when rainfall is around 1.6 in.

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 62.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 39.2 F).

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

Looking for the cheapest flight from Seattle to London Heathrow Airport? While on average our users pay $2,249, our data indicates the cheapest price to be $334. The most popular route (Seattle/Tacoma Intl - London Heathrow), is priced around $498.

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

No one likes to see their flight delayed. When booking a flight from Seattle to London Heathrow Airport consider choosing Air France (81%), KLM (81%) or Delta (80%) as they are the most reliable in getting you off to your destination on time.

What are the most popular airlines that fly from Seattle to London Heathrow Airport?

Before booking your flight from Seattle to London Heathrow Airport check out the most popular airlines for this route: British Airways, Delta or Virgin Atlantic.

Most accurate provider : When it comes to deals on Seattle-London Heathrow Airport flights, users find the pricing of CheapOair to be most consistent on Cheapflights vs. CheapOair Users can find the same prices on Seattle-London Heathrow Airport flight deals on Cheapflights vs. CheapOair >95% of the time. Price accuracy is based on data collected from Seattle-London Heathrow Airport flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Seattle-London Heathrow Airport flights, Cheapflights users trust CheapOair the most. CheapOair has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London Heathrow Airport flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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 14 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 14 airlines have flights from the Seattle airport to London Heathrow. It is only a 11.4 mi journey to Seattle/Tacoma Intl (SEA) from Seattle’s city center.

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.

$336+ Flights from Seattle to London Heathrow Airport

Q: How much does it cost to fly round-trip from Seattle to London Heathrow Airport?

Airfare is below average for this route at the moment. Seattle to London Heathrow Airport flights typically cost between $706 and $1,136 in February. The cheapest round-trip price found within the last 3 days was $575 on Icelandair (Feb 15-Feb 27).

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Find cheap flights from Seattle to Heathrow with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 Wednesday or Tuesday and return on a Wednesday

Cheap 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 December 23, 2025.

Tue 12/302:35 pmSEA - LHR

1 stop12h 15mIcelandair

Thu 1/2212:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$636

Mon 12/292:35 pmSEA - LHR

1 stop20h 55mIcelandair

Wed 1/2112:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$638

Tue 12/302:35 pmSEA - LHR

1 stop12h 15mIcelandair

Mon 1/198:35 pmLHR - SEA

1 stop28h 25mIcelandair

Deal found 12/21

$640

Mon 12/292:35 pmSEA - LHR

1 stop20h 55mIcelandair

Mon 1/128:35 pmLHR - SEA

1 stop28h 25mIcelandair

Deal found 12/22

$658

Sun 12/282:35 pmSEA - LHR

1 stop12h 15mIcelandair

Tue 1/2012:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$766

Tue 12/302:35 pmSEA - LHR

1 stop12h 15mIcelandair

Sun 1/1812:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$780

Mon 12/292:35 pmSEA - LHR

1 stop20h 55mIcelandair

Sun 1/1812:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$782

Sun 12/282:35 pmSEA - LHR

1 stop12h 15mIcelandair

Fri 1/2312:15 pmLHR - SEA

1 stop12h 45mIcelandair

Deal found 12/21

$789

Sun 12/282:35 pmSEA - LHR

1 stop12h 15mIcelandair

Mon 1/198:35 pmLHR - SEA

1 stop28h 25mIcelandair

Deal found 12/21

$791

Wed 12/313:10 pmSEA - LHR

1 stop13h 50mLufthansa

Thu 1/88:15 pmLHR - SEA

1 stop25h 05mLufthansa

Deal found 12/22

$798

Mon 12/297:20 pmSEA - LHR

Nonstop9h 30mDelta

Wed 1/2110:00 amLHR - SEA

1 stop33h 50mDelta

Deal found 12/21

$807

Tue 12/303:40 pmSEA - LHR

2 stops34h 30mLufthansa

Fri 1/236:35 amLHR - SEA

1 stop14h 45mLufthansa

Deal found 12/21

$811

Best flights from Seattle to Heathrow
Discover carefully curated flight deals from Seattle to Heathrow that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 23, 2025.

Wed 2/44:55 pmSEA - LHR

Nonstop9h 35mKLM

Wed 2/116:30 amLHR - SEA

1 stop13h 10mKLM

Deal found 12/22

$615

Sat 2/76:25 pmSEA - LHR

Nonstop9h 30mDelta

Sat 2/146:30 amLHR - SEA

1 stop13h 10mDelta

Deal found 12/22

$615

Fri 2/69:25 amSEA - LHR

2 stops20h 05mUnited Airlines

Fri 2/136:35 amLHR - SEA

1 stop14h 45mUnited Airlines

Deal found 12/23

$623

Mon 1/1910:58 amSEA - LHR

2 stops18h 02mSWISS

Mon 2/26:00 amLHR - SEA

2 stops24h 43mSWISS

Deal found 12/22

$638

Tue 2/176:25 pmSEA - LHR

Nonstop9h 30mKLM

Sun 3/16:30 amLHR - SEA

1 stop13h 05mKLM

Deal found 12/22

$615

Sun 3/85:40 pmSEA - LHR

Nonstop9h 50mDelta

Wed 3/186:20 amLHR - SEA

1 stop14h 45mDelta

Deal found 12/22

$620

Thu 2/55:50 amSEA - LHR

1 stop22h 00mUnited Airlines

Thu 2/1211:10 amLHR - SEA

1 stop34h 10mUnited Airlines

Deal found 12/22

$624

Mon 1/196:25 pmSEA - LHR

Nonstop9h 30mDelta

Mon 2/26:20 amLHR - SEA

1 stop15h 00mDelta

Deal found 12/22

$620

Sun 1/188:40 amSEA - LHR

2 stops16h 30mUnited Airlines

Sun 1/256:50 amLHR - SEA

2 stops23h 53mUnited Airlines

Deal found 12/21

$628

Mon 3/97:25 pmSEA - LHR

Nonstop9h 30mKLM

Mon 3/162:30 pmLHR - SEA

Nonstop10h 05mKLM

Deal found 12/22

$642

Mon 2/168:10 amSEA - LHR

2 stops52h 25mUnited Airlines

Sat 2/286:50 amLHR - SEA

2 stops20h 13mUnited Airlines

Deal found 12/22

$630

Mon 1/196:03 amSEA - LHR

2 stops23h 27mUnited Airlines

Mon 1/266:50 amLHR - SEA

2 stops23h 53mUnited Airlines

Deal found 12/22

$633

Last-minute flights from Seattle to Heathrow
Discover last-minute flight deals from Seattle to Heathrow. Data last updated December 23, 2025 and is based on user searches.

Sun 1/1810:05 amSEA - LHR

1 stop17h 45mLufthansa

Mon 1/268:15 pmLHR - SEA

2 stops31h 01mLufthansa

Deal found 12/21

$596

Sun 1/1812:35 pmSEA - LHR

2 stops21h 15mMultiple Airlines

Sun 1/257:40 amLHR - SEA

1 stop13h 40mMultiple Airlines

Deal found 12/21

$599

Sun 1/1810:05 amSEA - LHR

2 stops16h 05mMultiple Airlines

Mon 1/266:30 amLHR - SEA

1 stop13h 40mMultiple Airlines

Deal found 12/21

$602

Mon 1/193:40 pmSEA - LHR

1 stop12h 10mLufthansa

Mon 1/268:15 pmLHR - SEA

2 stops31h 01mLufthansa

Deal found 12/22

$589

Mon 1/199:55 amSEA - LHR

2 stops16h 15mLufthansa

Mon 2/26:30 amLHR - SEA

1 stop13h 40mLufthansa

Deal found 12/22

$594

Mon 1/193:40 pmSEA - LHR

1 stop12h 10mMultiple Airlines

Tue 1/276:35 amLHR - SEA

2 stops20h 41mMultiple Airlines

Deal found 12/21

$595

Tue 1/209:55 amSEA - LHR

2 stops16h 15mLufthansa

Tue 1/276:35 amLHR - SEA

2 stops20h 41mLufthansa

Deal found 12/22

$584

Wed 1/217:00 amSEA - LHR

1 stop14h 55mBrussels Airlines

Wed 1/286:50 amLHR - SEA

2 stops22h 07mBrussels Airlines

Deal found 12/22

$582

Wed 1/219:55 amSEA - LHR

1 stop17h 55mLufthansa

Sat 2/78:15 pmLHR - SEA

1 stop25h 05mLufthansa

Deal found 12/22

$593

Thu 1/227:00 amSEA - LHR

1 stop14h 55mLufthansa

Fri 1/306:30 amLHR - SEA

2 stops20h 46mLufthansa

Deal found 12/22

$598

Fri 1/233:40 pmSEA - LHR

1 stop12h 10mLufthansa

Mon 1/268:15 pmLHR - SEA

2 stops31h 01mLufthansa

Deal found 12/20

$590

Sat 1/2410:58 amSEA - LHR

2 stops18h 02mMultiple Airlines

Mon 2/26:30 amLHR - SEA

1 stop13h 40mMultiple Airlines

Deal found 12/21

$604

One-way flights from Seattle to Heathrow
Search for one-way flight options from Seattle to Heathrow. Find affordable one-way fares based on user searches. Data last updated December 23, 2025.

Wed 2/1810:09 amSEA - LHR

2 stops23h 21mMultiple Airlines

Deal found 12/22

$336

Sun 2/222:35 pmSEA - LHR

3 stops19h 55mMultiple Airlines

Deal found 12/22

$339

Tue 1/132:35 pmSEA - LHR

3 stops18h 15mMultiple Airlines

Deal found 12/22

$344

Sun 3/229:05 pmSEA - LHR

1 stop30h 05mAer Lingus

Deal found 12/22

$350

Wed 1/212:35 pmSEA - LHR

3 stops22h 30mMultiple Airlines

Deal found 12/21

$353

Wed 1/142:35 pmSEA - LHR

3 stops21h 15mMultiple Airlines

Deal found 12/22

$354

Fri 1/92:35 pmSEA - LHR

3 stops33h 30mMultiple Airlines

Deal found 12/21

$355

Tue 1/203:10 pmSEA - LHR

1 stop13h 40mWestJet

Deal found 12/21

$356

Wed 1/213:10 pmSEA - LHR

1 stop13h 40mWestJet

Deal found 12/21

$358

Tue 2/172:35 pmSEA - LHR

3 stops23h 05mMultiple Airlines

Deal found 12/21

$361

Thu 1/153:40 pmSEA - LHR

3 stops18h 10mMultiple Airlines

Deal found 12/22

$362

Thu 2/198:55 amSEA - LHR

2 stops24h 35mMultiple Airlines

Deal found 12/21

$363

Find flight deals from Seattle to Heathrow

Most accurate provider	CheapOair 3 stars
Most trusted provider	CheapOair 3 stars
Round-trip from	$575 (Cheapflightsfares)
One-way from	$336 (Kiwi.com)
Popular in	June
Cheapest in	October
Average price	$1,046
Good round-trip deal	$633 or less
Good one-way deal	$383 or less

Provider with most accurate pricing for Seattle/Tacoma Intl-London Heathrow flight deals.

Search Deals

Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-London Heathrow flights.

Search Deals

From Seattle/Tacoma Intl to London Heathrow

Search Deals

One-way flight from Seattle/Tacoma Intl to London Heathrow

Search Deals

Highest demand for flights based on searches. 18% potential increase in price ($177 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 3% potential price decrease ($29 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in December 2025

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

Use the filters below to find and compare flights from Seattle to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 2/4

4:55 pm-10:30 am

Nonstop9h 35m

London Heathrow

Wed 2/11

6:30 am-11:40 am

1 stop13h 10m

$615

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sat 2/7

6:25 pm-11:55 am

Nonstop9h 30m

London Heathrow

Sat 2/14

6:30 am-11:40 am

1 stop13h 10m

$615

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 2/17

6:25 pm-11:55 am

Nonstop9h 30m

London Heathrow

Sun 3/1

6:30 am-11:35 am

1 stop13h 05m

$615

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 3/8

5:40 pm-10:30 am

Nonstop9h 50m

London Heathrow

Wed 3/18

6:20 am-2:05 pm

1 stop14h 45m

$620

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/19

6:25 pm-11:55 am

Nonstop9h 30m

London Heathrow

Mon 2/2

6:20 am-1:20 pm

1 stop15h 00m

$620

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Fri 2/6

9:25 am-1:30 pm

2 stops20h 05m

London Heathrow

Fri 2/13

6:35 am-1:20 pm

1 stop14h 45m

$623

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 2/5

5:50 am-11:50 am

1 stop22h 00m

London Heathrow

Thu 2/12

11:10 am-1:20 pm

1 stop34h 10m

$624

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 1/18

8:40 am-9:10 am

2 stops16h 30m

London Heathrow

Sun 1/25

6:50 am-10:43 pm

2 stops23h 53m

$628

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 2/16

8:10 am-8:35 pm

2 stops52h 25m

London Heathrow

Sat 2/28

6:50 am-7:03 pm

2 stops20h 13m

$630

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/19

6:03 am-1:30 pm

2 stops23h 27m

London Heathrow

Mon 1/26

6:50 am-10:43 pm

2 stops23h 53m

$633

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/22

Showing 1-10 of 23 results

Compare providers for flights from Seattle to Heathrow

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to Heathrow in December.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy2 stars	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*1 star
eDreams	Price Accuracy3 stars	Trust Score*3 stars
AranGrant	Price Accuracy2 stars	Trust Score*3 stars
Cheapflightsfares	Price Accuracy3 stars	Trust Score*2 stars
Ovago	Price Accuracy2 stars	Trust Score*2 stars
Justfly.com	Price Accuracy3 stars	Trust Score*3 stars
Trip.com	Price Accuracy2 stars	Trust Score*3 stars
JustAirTicket	Price Accuracy-	Trust Score*1 star
CheapOair	Price Accuracy3 stars	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Seattle-London Heathrow Airport flights, users find the pricing of CheapOair to be most consistent on Cheapflights vs. CheapOair Users can find the same prices on Seattle-London Heathrow Airport flight deals on Cheapflights vs. CheapOair >95% of the time. Price accuracy is based on data collected from Seattle-London Heathrow Airport flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Seattle-London Heathrow Airport flights, Cheapflights users trust CheapOair the most. CheapOair has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-London Heathrow Airport flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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

Prices

Airlines

Delays

How far ahead should I book a flight from Seattle to London Heathrow Airport?

Booking 65 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to London Heathrow Airport. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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 $498). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $790). 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?

When flying from Seattle to London Heathrow Airport, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 15% versus a flight in the morning.

What is the cheapest day to fly from Seattle to London Heathrow Airport?

Travelers seeking maximum savings on their Seattle to London Heathrow Airport flight should consider departing on Monday mornings when fares are most often at their lowest. Thursday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

How much does it cost to fly round-trip from Seattle to London Heathrow Airport?

The best insider tips for Seattle to London Heathrow Airport flights

Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to London Heathrow Airport trip

Airports

SEA

Use SEA Spot Saver to book security screening appointments in advance, reducing wait times without needing TSA PreCheck or CLEAR.

LHR

Take the Heathrow Express for the fastest route to central London, reaching Paddington Station quickly and conveniently.

Our travel experts

Ramsey Qubein

Expert on LHR

Brandon Schultz

Expert on SEA

Reviews of airlines servicing Heathrow

Read reviews from past customers who have flown Delta, Virgin Atlantic, and Icelandair from Seattle to London Heathrow Airport. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.

Delta

7.9

Good

8,015 reviews

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Virgin Atlantic

7.5

Good

677 reviews

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Icelandair

7.0

Good

592 reviews

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Iberia

7.0

Good

3,056 reviews

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

British Airways

6.7

Okay

7,607 reviews

Delta

7.9

Good

8,015 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Related info for your journey

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 14 outbound flights to London Heathrow per day. You should also have plenty of airline options to choose from since 14 airlines have flights from the Seattle airport to London Heathrow. It is only a 11.4 mi journey to Seattle/Tacoma Intl (SEA) from Seattle’s city center.
How long is the flight from Seattle to London Heathrow Airport?
For as low as $615, KLM can have you in London Heathrow Airport from Seattle in 9h 30m. The distance between Seattle and London Heathrow Airport is about 4783 mi. All flights are typically nonstop.
What are the cheapest airlines flying from Seattle to London Heathrow Airport round-trip?
Our cheapest airline available from Seattle to London Heathrow Airport is Scandinavian Airlines. Our recent data shows that you can find tickets from as low as $465 on this airline. Additional options worth looking into are Icelandair and Aer Lingus, starting at $480 and $500 round-trip. Scandinavian Airlines is currently priced 41% below the average price you’ll pay for this route.
What are the cheapest airlines to fly from Seattle to London Heathrow Airport one-way?
The cheapest airlines for a one-way flight from Seattle to London Heathrow Airport are Icelandair ($166), WestJet ($222), and Aer Lingus ($362).
What are the most reliable airlines from Seattle to London Heathrow Airport?
No one likes to see their flight delayed. When booking a flight from Seattle to London Heathrow Airport consider choosing Air France (81%), KLM (81%) or Delta (80%) as they are the most reliable in getting you off to your destination on time.
What are the cheapest flights from Seattle to London Heathrow Airport?
Looking for the cheapest flight from Seattle to London Heathrow Airport? While on average our users pay $2,249, our data indicates the cheapest price to be $334. The most popular route (Seattle/Tacoma Intl - London Heathrow), is priced around $498.
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, October is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of $498). Flying from Seattle to London Heathrow Airport in June is currently the most expensive (average of $790). 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.

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Top 10 airlines flying from Seattle to Heathrow

Airline	Cheapest	Average	Flexibility	On-time
Scandinavian Airlines	Cheapest$465	Average$718	FlexibilityNo cancel fee	On-time77%
Icelandair	Cheapest$481	Average$630	FlexibilityNo cancel fee	On-time76%
Aer Lingus	Cheapest$500	Average$700	FlexibilityNo cancel fee	On-timeN/A
American Airlines	Cheapest$517	Average$817	FlexibilityNo cancel fee	On-time71%
Air France	Cheapest$532	Average$765	FlexibilityNo cancel fee	On-time77%
British Airways	Cheapest$544	Average$783	FlexibilityNo cancel fee	On-time70%
United Airlines	Cheapest$547	Average$822	FlexibilityNo cancel fee	On-time69%
Alaska Airlines	Cheapest$553	Average$999	FlexibilityNo cancel fee	On-time75%
Finnair	Cheapest$556	Average$694	FlexibilityNo cancel fee	On-time76%
Delta	Cheapest$563	Average$836	FlexibilityNo cancel fee	On-timeN/A

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$336+ Cheap flights from Seattle (SEA) to Heathrow (LHR)

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 2/18. Fares are subject to change and may not be available on all flights or dates of travel.

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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 Wednesday or Tuesday and return on a Wednesday

Cheap flight deals from Seattle to Heathrow

Cheapest flights from Seattle to HeathrowExplore 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 December 23, 2025.

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 December 23, 2025.

Find flight deals from Seattle to Heathrow

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Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to Heathrow in December.

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.

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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?

What is the cheapest month to book a flight from Seattle to London Heathrow Airport?

What is the cheapest time of day to fly from SEA to LHR?

What is the cheapest day to fly from Seattle to London Heathrow Airport?

How much does it cost to fly round-trip from Seattle to London Heathrow Airport?

Weekly flight availability from Seattle to London Heathrow Airport

How often are flights from Seattle to London delayed?

What is the most punctual flight time for Seattle to London flights?

What day of the week experiences the fewest flight delays on this route?

Which airline has the best punctuality record on Seattle to London flights?

What’s the top layover airport for flights from Seattle to London Heathrow Airport?

What’s the cheapest layover airport for flights from Seattle to London Heathrow Airport?

What’s the fastest layover option from Seattle to London Heathrow Airport?

Which airport typically offers the quickest layover for flights from Seattle to London Heathrow Airport?

The best insider tips for Seattle to London Heathrow Airport flights

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Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to London Heathrow Airport trip

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Reviews of airlines servicing Heathrow

Read reviews from past customers who have flown Delta, Virgin Atlantic, and Icelandair from Seattle to London Heathrow Airport. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.

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?

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

What are the cheapest airlines to fly from Seattle to London Heathrow Airport one-way?

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

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

Can I find deals for flights from Seattle to Heathrow that include hotel bookings?

How can I find direct flights from Seattle to Heathrow?

Can I find deals for business class flights from Seattle to Heathrow?

What is the cheapest month to book a flight from Seattle to London Heathrow Airport?

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Top 10 airlines flying from Seattle to Heathrow

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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 December 23, 2025.