Cheap flights from London Heathrow Airport to Seattle from $737

The month of January is, on average, the cheapest month to fly to Seattle from London Heathrow Airport, with most prices found around $961. If you are unable to visit Seattle during the month of January, then departing from London Heathrow Airport during the month February is also very affordable. Most momondo users find prices during this month for around $962.

The cheapest day to depart from London Heathrow Airport to Seattle is on a Monday. Travellers who choose to depart for Seattle on a Monday will often find tickets for as low as $1,009. When flying out on a Thursday, the most expensive travel day of the week, you can expect to see flight prices from London Heathrow Airport to Seattle for around $1,588.

According to our data, the cheapest time of day to fly to Seattle is in the afternoon. momondo users have found flights departing from London Heathrow Airport to Seattle in the afternoon for as low as $1,542. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. In contrast, the most expensive time of day to depart to Seattle is in the morning when prices are around $1,577.

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 $1,133 when searching weeks before you fly. 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 $1,042 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.

Historically, on average around 11% 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 130 minutes.

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

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

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

The number of flights available between London Heathrow Airport and Seattle is 22 per day as of September 2026. The most frequent departure time is 09:00, with 52% of daily flights leaving in the afternoon.

As of September 2026, 155 flights take off from London Heathrow Airport and land in Seattle each week. The most common flight departure day for this route is Tue, with 15% of weekly flights taking off on this day.