Cheap flights from London Heathrow Airport to Seattle from $518

In general, January is the cheapest month to fly from London Heathrow Airport to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $647. If you don’t want to visit Seattle in January, then you should wait until February to fly from London Heathrow Airport, when ticket prices are also cheap, with an average price of $656.

On average, the least expensive day to fly to Seattle from London Heathrow Airport is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as $771. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Saturday is the most expensive day to depart from London Heathrow Airport because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $893.

Flying to Seattle from London Heathrow Airport at noon is the least expensive time of day to depart. momondo users have found prices as low as $672 when looking at flights departing at noon. Flights to Seattle are more costly in the morning, with an average ticket price of $877. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to Seattle from London Heathrow Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $785 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from London Heathrow Airport for as low as $728 on momondo.

There are 3 cabin classes available to choose from on London Heathrow Airport to Seattle flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Alaska Airlines, Virgin Atlantic, and United Airlines are the most popular carriers operating from London Heathrow to Seattle/Tacoma Intl

British Airways, Delta and Virgin Atlantic are the top three most popular airlines that fly to Seattle from London Heathrow Airport according to our data. British Airways is the first choice among our users, with 30% of people opting to fly with this airline when traveling to Seattle. Keep in mind that there are 6 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.

Historically, on average around 12% of flights between London and Seattle have experienced a delay on any given week. The average delay length over the past 12 months has been 134 minutes.

Generally, flights departing in the evening tend to experience fewer delays. Flights in the early afternoon have, in the past, seen delays more frequently in comparison.

Sunday is statistically the day of the week which experiences the fewest number of delays on this flight route. Friday has historically seen more delays on average compared to the rest of the week.

According to our data, Delta have had the least number of delays on this route over the last 12 months; with about 5% of their flights experiencing any sort of delay.

As of October 2026, 9 flights take off from London Heathrow Airport and land in Seattle each day. The most common flight departure time for this route is 5:00PM, with 54% of daily flights taking off in the afternoon.

63 flights are operational weekly from London Heathrow Airport to Seattle as of October 2026. The most popular departure day for this route is Thu, with 30% of flights per week taking off on this day.