Question 1

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

Accepted Answer

Cheapflights users have booked flights from Seattle to London Heathrow Airport round-trip from £488. Other airlines that can offer you cheap pricing are Delta, from £489, and Icelandair, from £490. You may be able to fly from Seattle to London Heathrow Airport for 18% less than the average price by searching for these airlines.

Question 2

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

Accepted Answer

One-way options have recently been found by users for as low as £187 on Icelandair. Other airlines that offer cheap prices include WestJet from £238 and JetBlue from £251 one-way.

Question 3

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

Accepted Answer

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 32 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Question 4

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

Accepted Answer

Currently, January is the cheapest month in which you can book a flight from Seattle to London Heathrow Airport (average of £112). Flying from Seattle to London Heathrow Airport in August is currently the most expensive (average of £164). 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.

Question 5

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

Accepted Answer

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

Question 6

Weekly flight availability from Seattle to London Heathrow Airport

Accepted Answer

The most flights from SEA to LHR are scheduled on a Monday (22 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (16 on average).

Question 7

E

Accepted Answer

In terms of precipitation, rainfall in London Heathrow Airport ranges from 40.0 - 70.0 inches per month. January is typically the wettest month, when rainfall can reach 70.0 mm. July is typically the driest time to visit London Heathrow Airport when rainfall is around 40.0 mm.

Question 8

E

Accepted Answer

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 17.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 4.0 C).

Question 9

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

Accepted Answer

While on average a flight from Seattle to London Heathrow Airport is generally £1,296, our data shows the cheapest flight currently is £292. When looking at the most popular route, (Seattle/Tacoma Intl - London Heathrow), you can expect to pay £320 for that flight.

Question 10

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

Accepted Answer

Consider Aeromexico (92%), KLM (87%) or Air France (87%) when booking your flight. These represent the most reliable airlines when flying from Seattle to London Heathrow Airport.

Question 11

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

Accepted Answer

When booking a flight from Seattle to London Heathrow Airport, you may want to consider flying on British Airways, Icelandair or Virgin Atlantic as they are the most popular for this route.

Question 12

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

Accepted Answer

Departing on a Monday is a good option for securing a great price. You can expect to save up to 37% when planning your travel around this day of the week.

Question 13

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

Accepted Answer

Travelers have found it’s best to book a flight 35 days in advance to save up to 38% compared to booking the same week of travel. As your travel date approaches, the cost of this flight route may potentially increase. While opting to book 35 days out may not be an option for all, there are still additional ways to secure a deal in the near future. You might find a flight from Seattle to London Heathrow Airport 1-2 weeks in advance for as low as £619, or £722 for flights within the next 24 hours.

Question 14

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

Accepted Answer

Due to multiple factors, expect to potentially pay more when booking in June. For low rates, January can be a great choice for travel to London Heathrow Airport. Flights to London Heathrow Airport from Seattle in January are about £575 on average during January, but can be found for as low as £365.

Question 15

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

Accepted Answer

Unlike in the morning, when flights are generally more expensive, you can save up to 8% on flights from Seattle to London Heathrow Airport by exploring options for tickets at midday.

Question 16

What airport do you fly from for flights from Seattle to London Heathrow?

Accepted Answer

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 21 flights from Seattle/Tacoma Intl to London Heathrow per day from 3 different airlines.

Question 17

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

Accepted Answer

Yes. In addition to deals on Seattle to Heathrow flights, Cheapflights offers holiday packages that include both flights and hotel.

Question 18

How can I find direct flights from Seattle to Heathrow?

Accepted Answer

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Heathrow.

Question 19

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

Accepted Answer

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.

Question 20

How does Cheapflights help users find flights from Seattle to Heathrow?

Accepted Answer

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.

Question 21

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

Accepted Answer

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!

Question 22

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

Accepted Answer

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

Question 23

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

Accepted Answer

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!

Round-trip from	£488
One-way from	£187
Popular in	June
Cheapest in	March
Average price	£821
Good round-trip deal	£483 or less
Good one-way deal	£301 or less

Airline	Cheapest	Average	Flexibility	On-time
Icelandair	Cheapest£356	Average£487	FlexibilityNo cancel fee	On-time76%	Search Icelandair flights
Virgin Atlantic	Cheapest£442	Average£635	FlexibilityNo cancel fee	On-time72%	Search Virgin Atlantic flights
British Airways	Cheapest£446	Average£728	FlexibilityNo cancel fee	On-time70%	Search British Airways flights

Cheap flights from Seattle to London Heathrow Airport from £187

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 27/10. Fares are subject to change and may not be available on all flights or dates of travel.

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 Tuesday or Monday and return on a Tuesday

Cheap flight deals from Seattle to Heathrow

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

Good one-way deal

Find 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 13 June 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 13 June 2025.

Cheapflights Fare Finder

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

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.

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 9 June 2025.

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?

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 13 June 2025.

Weekly flight availability from Seattle to London Heathrow Airport

Explore weekly flight availability from Seattle to Heathrow. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 13 June 2025.

Rainfall in Heathrow by month

Plan your trip to Heathrow by taking into account the average rainfall totals by month.

Temperature in Heathrow by month

Plan your trip to Heathrow by taking into account the average temperature totals by month.

Reviews of airlines servicing Heathrow

Read reviews from past customers who have flown Delta, Air France and SWISS from Seattle to London. Reviews also offer insight into each airline's 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?

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?

Travelling to a place near Seattle?

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.

Alternative routes for Seattle to Heathrow

See prices for flight routes from nearby airports that may be better suited for you.

Top 3 airlines flying from Seattle to Heathrow

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?

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

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

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

100% Free

Book with Flexibility

Travel Smart

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 13 June 2025.