Cheap flights from Seattle to the United Kingdom from $173

In general, January is the cheapest month to fly from Seattle to United Kingdom. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $641. If you aren’t able to travel to United Kingdom during the month of January, then flying in October is also cheap. Prices for this month can be found on momondo for an average of $647.

The cheapest day to depart from Seattle to United Kingdom is on a Wednesday when prices can be found for as low as $771. The most expensive day to fly to United Kingdom is Friday, with ticket prices averaging around $875.

According to our data, the cheapest time of day to fly to United Kingdom is at noon. momondo users have found flights departing from Seattle to United Kingdom at noon for as low as $809. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights to United Kingdom are more costly in the afternoon, with an average ticket price of $839. Departure times in the afternoon fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to United Kingdom from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to United Kingdom for around $777 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to United Kingdom from Seattle for as low as $678 on momondo.

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

Icelandair, United Airlines, and British Airways are the most popular carriers operating from Seattle/Tacoma Intl to United Kingdom

British Airways, Delta and Icelandair are the top three most popular airlines that fly to United Kingdom from Seattle according to our data. British Airways is the first choice among our users, with 38% of people opting to fly with this airline when traveling to United Kingdom. Keep in mind that there are 15 different airlines that fly to United Kingdom on a routine basis, so you have a few additional options to choose from.

Historically, on average around 16% of flights between Seattle and United Kingdom have experienced a delay on any given week. The average delay length over the past 12 months has been 123 minutes.

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

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

According to our data, Virgin Atlantic have had the least number of delays on this route over the last 12 months; with about 7% of their flights experiencing any sort of delay.

The number of flights available between Seattle and United Kingdom is 13 per day as of February 2026. The most frequent departure time is 6:00PM, with 54% of daily flights leaving in the evening.

As of February 2026, there are 93 flights per week flying from Seattle to United Kingdom. The most common day of the week flights depart is Tue, with 23% of flights taking off on this day.