Cheap flights from Seattle to Philadelphia from $138

The cheapest month to fly to Philadelphia from Seattle is in October. Flight prices, which tend to average around $327, are often lower during this time because this is during the off-season. The month of January is another great option to travel to Philadelphia, with average flight prices from Seattle averaging around $337.

The cheapest day to depart from Seattle to Philadelphia is on a Tuesday. Travelers who choose to depart for Philadelphia on a Tuesday will often find tickets for as low as $441. On the other hand, Sunday is the most expensive day to depart from Seattle because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $569.

According to our data, the cheapest time of day to fly to Philadelphia is in the evening. momondo users have found flights departing from Seattle to Philadelphia in the evening for as low as $453. 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 Philadelphia is in the afternoon when prices are around $726.

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

You are more likely to see cheaper flights to Philadelphia from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to Philadelphia for around $421 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Philadelphia from Seattle for as low as $369 on momondo.

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

You could potentially save up to 10% on your flight if you consider stops on a Seattle to Philadelphia flight.

As of April 2026, prices for Seattle to Philadelphia flights are approximately 8% cheaper when compared to flights at the same time last year.

Frontier and Southwest are the most popular carriers operating from Seattle/Tacoma Intl to Philadelphia

Alaska Airlines, American Airlines and United Airlines are the top three most popular airlines that fly to Philadelphia from Seattle according to our data. Alaska Airlines is the first choice among our users, with 54% of people opting to fly with this airline when traveling to Philadelphia. Keep in mind that there are 10 different airlines that fly to Philadelphia on a routine basis, so you have a few additional options to choose from.

Denver (DEN) was the most common stop: 43% of momondo users choosing 1-stop flights on this route connected there.

Flights via Detroit (DTW) offer the lowest average round-trip price of $256.

Flights connecting via Salt Lake City (SLC) have the shortest average one-way travel time: 7h 06m.

Salt Lake City (SLC) has the shortest average layover time for this route: 0h 55m.

As of April 2026, 3 flights take off from Seattle and land in Philadelphia each day. The most common flight departure time for this route is 12:00PM, with 42% of daily flights taking off in the afternoon.

27 flights are operational weekly from Seattle to Philadelphia as of April 2026. The most popular departure day for this route is Wed, with 26% of flights per week taking off on this day.