Cheap flights from Boston to Seattle from $128

In general, May is the cheapest month to fly from Boston to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $311. If you don’t want to visit Seattle in May, then you should wait until September to fly from Boston, when ticket prices are also cheap, with an average price of $317.

On average, the least expensive day to fly to Seattle from Boston is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as $405. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from Boston because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $507.

Flying to Seattle from Boston in the evening is the least expensive time of day to depart. momondo users have found prices as low as $375 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $464. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

Fly from Boston Logan Intl to Seattle/Tacoma Intl for the best Boston Logan Intl - Seattle/Tacoma Intl flight prices

You are more likely to see cheaper flights to Seattle from Boston when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $377 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from Boston for as low as $320 on momondo.

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

United Airlines and Delta are the most popular carriers operating from Boston Logan Intl to Seattle/Tacoma Intl

Delta, Alaska Airlines and JetBlue are the top three most popular airlines that fly to Seattle from Boston according to our data. Delta is the first choice among our users, with 36% of people opting to fly with this airline when traveling to Seattle. Keep in mind that there are 8 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.

Historically, on average around 14% of flights between Boston and Seattle have experienced a delay on any given week. The average delay length over the past 12 months has been 164 minutes.

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

Monday is statistically the day of the week which experiences the fewest number of delays on this flight route. Saturday 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 13% of their flights experiencing any sort of delay.

As of March 2026, there are 8 flights per day flying from Boston to Seattle. The most common time of day flights depart is 7:00AM, with 71% of flights taking off at noon.

The number of flights available between Boston and Seattle is 62 per week as of March 2026. The most frequent departure day is Sat, with 32% of weekly flights leaving on this day.