Flights from Seattle to London available from USD 628*

The average flight duration from Seattle to London Gatwick or Heathrow Airport is approximately 9 hours and 30 minutes non-stop, though this estimate does not include any planned stopovers.

When you book flights to London from Seattle with Icelandair, passengers have the option to extend their stay in Iceland for up to seven days.

The optimal time to fly to London from Seattle largely depends on your personal preferences and travel needs.

While summer is characterized by long, bright days – perfect for outdoor events and sightseeing, spring (April to June) and early fall (September) tend to offer lower airfares, and the weather is still pleasant.

Passengers booking plane tickets from Seattle to London can fly into London Heathrow Airport (LHR) or Gatwick Airport (LGW).

You can use the flight finder tool above to select flights to your desired airport.

Passengers flying from Seattle to London with Icelandair will transfer at Keflavík International Airport. From there, you will fly directly to London Heathrow or Gatwick airport.

The flight time from KEF to LHR/LGW is around 3 hours.

Being flexible about which season you fly during, as well as which London airport you depart from can help you find a good deal on your tickets. Flying on a weekday may also help you secure a lower airfare, too.

We also recommend checking our flight deals page regularly and booking in advance.