Question 1

Which airport is the most popular layover for flights between Seattle and London?

Accepted Answer

Reykjavik (KEF) was the most common stop: 77% of momondo users choosing 1-stop flights on this route connected there.

Question 2

What is the cheapest airline that flies from Seattle/Tacoma Intl to London?

Accepted Answer

WestJet is the most popular carrier operating from Seattle/Tacoma Intl to London

Question 3

How far in advance should I book a flight to London?

Accepted Answer

You are more likely to see cheaper flights to London from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to London for around $804 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London from Seattle for as low as $701 on momondo.

Question 4

What is the cheapest time of day to depart on your flight to London?

Accepted Answer

Flying to London from Seattle in the evening is the least expensive time of day to depart. momondo users have found prices as low as $846 when looking at flights departing in the evening. Flights to London are more costly in the morning, with an average ticket price of $980. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

Question 5

What airlines fly to London?

Accepted Answer

British Airways, Delta and Virgin Atlantic are the top three most popular airlines that fly to London from Seattle according to our data. British Airways is the first choice among our users, with 37% of people opting to fly with this airline when traveling to London. Keep in mind that there are 15 different airlines that fly to London on a routine basis, so you have a few additional options to choose from.

Question 6

What cabin class options are available on Seattle/Tacoma Intl to London flights?

Accepted Answer

There are 4 cabin classes available to choose from on Seattle/Tacoma Intl to London flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Question 7

Which layover airport offers the lowest fares from Seattle to London?

Accepted Answer

Flights via Boston (BOS) offer the lowest average round-trip price of $652.

Question 8

What is the cheapest month to fly to London?

Accepted Answer

The cheapest month to fly to London from Seattle is in October. Flight prices, which tend to average around $664, are often lower during this time because this is during the off-season. The month of January is another great option to travel to London, with average flight prices from Seattle averaging around $674.

Question 9

What is the cheapest day to depart on your flight to London?

Accepted Answer

The cheapest day to depart from Seattle to London is on a Tuesday. Travelers who choose to depart for London on a Tuesday will often find tickets for as low as $813. If your travel schedule is flexible, try to avoid departing on a Saturday because tickets tend to average around $931. These prices are subject to change though, so be sure to set up a Price Alert for flights to London.

Question 10

How have Seattle to London flight prices changed over time?

Accepted Answer

As of August 2025, prices for Seattle to London flights are approximately 55% cheaper when compared to flights at the same time last year.

Question 11

Which layover airport has the shortest travel time from Seattle to London?

Accepted Answer

Flights connecting via Reykjavik (KEF) have the shortest average one-way travel time: 12h 09m.

Question 12

How many flights depart from Seattle to London on average per week?

Accepted Answer

145 flights are operational weekly from Seattle to London as of August 2025. The most popular departure day for this route is Wed, with 17% of flights per week taking off on this day.

Question 13

Which layover airport has the shortest connection time from Seattle to London?

Accepted Answer

Dublin (DUB) has the shortest average layover time for this route: 1h 54m.

Question 14

What is the cheapest Seattle/Tacoma Intl to London flight route?

Accepted Answer

Fly from Seattle/Tacoma Intl to London Heathrow for the best Seattle/Tacoma Intl - London flight prices

Question 15

How many flights depart from Seattle to London on average per day?

Accepted Answer

As of August 2025, 20 flights take off from Seattle and land in London each day. The most common flight departure time for this route is 8:00PM, with 53% of daily flights taking off in the evening.

Question 16

Which airlines fly direct from Seattle to London?

Accepted Answer

Conveniently, you have a few options when it comes to flying nonstop from Seattle International Airport (SEA) to Heathrow Airport (LHR) in London. British Airways has two direct flights daily, while Virgin Atlantic, American Airlines, and Delta Airlines all offer one direct flight daily. The flight time is generally around 9h 30min. There are also multiple airlines that offer one-stop flights between SEA and LHR. These include United/Lufthansa, Air Canada, Finnair, Aer Lingus, Alaska/Icelandair, and more. These flights can take anywhere from 12 hours to 16 hours or more, depending on your layover time (which varies). Stopover cities include Amsterdam, Paris, and others. Currently, there are no direct flights between SEA and London Gatwick (LGW). There are also one-stop flights from London City Airport (LCY) and London Luton Airport (LTN), and two-stop flights from London Stansted Airport (STN).

What is the best way to get in and out of airports in Seattle and London?

Upon landing in Seattle and London, you have multiple options for navigating from the airport to your destination. It’s easy to get from Seattle-Tacoma International Airport (SEA) to downtown Seattle. You can use the Link Light Rail, which has trains departing every ten minutes or so. To get to the station from baggage claim, head up to the fourth floor and cross the skybridge to get to the parking garage level; there’s ample signage to guide you. This is the most cost-effective option. You can also opt to hail a cab, take a rideshare, or rent a car. Heathrow Airport (LHR) offers robust public transportation to get you from the airport to Central London. The fastest option is the Heathrow Express, which runs non-stop trains every 15 minutes (it takes just 15 minutes to make the journey). It’s also possible to rent a car or hail a cab (the latter is the most expensive option). That said, most locals take public transit because of how ubiquitous and convenient it is. In addition, you can take the Gatwick Express train to get from LGW to Central London; LCY is accessible via the Tube, bus, rental car, or taxi; or, travel from STN by bus, train, taxi, or rental car.

What are the benefits of the different airports in Seattle and London?

Seattle-Tacoma International Airport (SEA) is a destination in and of itself. You’ll find a great mix of local bookstores (like the popular Elliott Bay Book Company), cafes, restaurants, bars, and shops here. In addition, specialty services include massage options, shoeshine, manicures and pedicures, and more. While there are six airports in the London area, the two major ones are Heathrow (LHR) and Gatwick (LGW). There are some key differences between the two. Namely, LHR serves nearly every airline under the sun, so you have plenty of options when it comes to choosing a flight. As you might imagine, this airport also has a staggering number of shops, restaurants, and pubs. Premium lounges and spa services are available throughout. The biggest benefit to flying into LGW is that this airport can sometimes have cheaper flights (budget airlines like easyJet operate from here), and it’s generally not that crowded, so you don't have to worry about waiting in line for a long time at security. In terms of other airports in London, LTN has two top-notch lounges; LCY is the closest airport to Central London; and, STN serves over 160 destinations.

What cities can you get to from Heathrow Airport in London?

For travelers who want to explore other international cities, LHR makes for an excellent base. There are daily flights from this major hub to tons of exciting global hot spots, including Dubai, Tokyo, Amsterdam, Havana, Mexico City, Zurich, Milan, Nairobi, Perth, São Paulo, Tel Aviv, and more. Traveling to the U.S.? You can opt to fly Delta, American, or United to most major cities, such as San Diego, Austin, Denver, New Orleans, Nashville, Boston, Charlotte, Detroit, Newark, Los Angeles, Phoenix, Dallas, Kauai, New York, and Tampa (just to name a few). Access Amsterdam, Bucharest, Budapest and other European cities from LTN; fly to Barcelona, Dublin, Prague, and others from LCY; go to Milan, Seville, Lisbon, and other cities from STN.

Question 17

When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London?

Accepted Answer

Prices for flights from Seattle/Tacoma Intl Airport to London are refreshed on a daily basis.

Question 18

How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London?

Accepted Answer

The number of operators available for flights from Seattle/Tacoma Intl Airport to London is 15 as of August 2025.

Question 19

How old do you have to be to fly from Seattle/Tacoma Intl Airport to London?

Accepted Answer

The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Seattle/Tacoma Intl Airport to London.

Question 20

What documentation or ID do you need to fly to London?

Accepted Answer

The travel and health documents you'll need for your trip to London may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

Best Price Found	$452
Fastest flight time	9h 20m
Direct flights	Every day
Airports in London	1 airport

Airline	Rating	Free Cancellation	Price
Lufthansa	PriceFrom $378	Free Cancellation	Rating 6.8 7,344 reviews	Search Lufthansa flights
Icelandair	PriceFrom $497	Free Cancellation	Rating 7.0 529 reviews	Search Icelandair flights
Scandinavian Airlines	PriceFrom $532	Free Cancellation	Rating 7.4 1,471 reviews	Search Scandinavian Airlines flights
Air France	PriceFrom $532	Free Cancellation	Rating 7.4 1,469 reviews	Search Air France flights
United Airlines	PriceFrom $547	Free Cancellation	Rating 7.4 8,930 reviews	Search United Airlines flights
Finnair	PriceFrom $556	Free Cancellation	Rating 7.6 1,320 reviews	Search Finnair flights
British Airways	PriceFrom $564	Free Cancellation	Rating 6.7 7,291 reviews	Search British Airways flights
Delta	PriceFrom $574	Free Cancellation	Rating 7.9 7,981 reviews	Search Delta flights
Aer Lingus	PriceFrom $576	Free Cancellation	Rating 7.1 1,228 reviews	Search Aer Lingus flights
Iberia	PriceFrom $578	Free Cancellation	Rating 7.0 2,884 reviews	Search Iberia flights

Cheap flights from Seattle to London from $243

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What is the cheapest month to fly to London?

What is the cheapest day to depart on your flight to London?

What is the cheapest time of day to depart on your flight to London?

What is the cheapest Seattle/Tacoma Intl to London flight route?

Fly from Seattle/Tacoma Intl to London Heathrow for the best Seattle/Tacoma Intl - London flight prices

How far in advance should I book a flight to London?

What cabin class options are available on Seattle/Tacoma Intl to London flights?

There are 4 cabin classes available to choose from on Seattle/Tacoma Intl to London flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Seattle to London flight prices changed over time?

As of August 2025, prices for Seattle to London flights are approximately 55% cheaper when compared to flights at the same time last year.

What is the cheapest airline that flies from Seattle/Tacoma Intl to London?

WestJet is the most popular carrier operating from Seattle/Tacoma Intl to London

What airlines fly to London?

Which airport is the most popular layover for flights between Seattle and London?

Reykjavik (KEF) was the most common stop: 77% of momondo users choosing 1-stop flights on this route connected there.

Which layover airport offers the lowest fares from Seattle to London?

Flights via Boston (BOS) offer the lowest average round-trip price of $652.

Which layover airport has the shortest travel time from Seattle to London?

Flights connecting via Reykjavik (KEF) have the shortest average one-way travel time: 12h 09m.

Which layover airport has the shortest connection time from Seattle to London?

Dublin (DUB) has the shortest average layover time for this route: 1h 54m.

How many flights depart from Seattle to London on average per day?

As of August 2025, 20 flights take off from Seattle and land in London each day. The most common flight departure time for this route is 8:00PM, with 53% of daily flights taking off in the evening.

How many flights depart from Seattle to London on average per week?

145 flights are operational weekly from Seattle to London as of August 2025. The most popular departure day for this route is Wed, with 17% of flights per week taking off on this day.

When to book flights from Seattle to London

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How old do you have to be to fly from Seattle/Tacoma Intl Airport to London?

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