$89 Cheap Flights from Seattle (SEA) to Philadelphia (PHL)

Popular airlines from Seattle-Tacoma International Airport (SEA) to Philadelphia Intl. Airport (PHL)

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Find available prices by choosing your travel dates.

Cheap Flights from Seattle to Philadelphia (SEA-PHL)

Prices were available within the past 7 days and start at $89 for one-way flights and $165 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Frontier Airlines
Frontier Airlines
Spirit Airlines
Frontier Airlines
Spirit Airlines
Spirit Airlines
American Airlines
United
Southwest Airlines
Flights from Seattle (SEA) to Philadelphia (PHL)
Origin airport
Seattle - Tacoma Intl.
Destination airport
Philadelphia Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, JetBlue Airways, Southwest Airlines, Spirit Airlines, Sun Country Airlines, United
Roundtrip price
$165
Distance
2371 mi

Seattle to Philadelphia Flights

The cheapest times to fly from Seattle to Philadelphia

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Seattle to Philadelphia are during the month of May. You can find some of the cheapest flights from Seattle to Philadelphia with Expedia's search tool and vast selection of airlines.

The best time to book a flight from Seattle to Philadelphia

Sunday is one of the best days to book for cheap flights from Seattle to Philadelphia: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

How to find cheap round-trip tickets from Seattle to Philadelphia

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Seattle to Philadelphia in 2025. You can also book with separate airlines for your outbound and return journeys, from $89 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Seattle to Philadelphia flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

You could also save big by booking one of Expedia's vacation packages. Bundling together your Seattle to Philadelphia airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

*Terms apply.

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

Frequently asked questions

How long does it take to fly from Sea-Tac Airport to Philadelphia Airport?
With Alaska Airlines, a direct flight takes roughly 5 hours and 12 minutes. Step on board the 9:33PM flight from SEA and touch down at Philadelphia Intl. Airport (PHL) at 5:45AM. Grab a top deal on this route when you book your ticket with Expedia.
Is it cheaper to buy a plane ticket from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) last minute?
Booking your journey from Sea-Tac Airport to PHL last minute could save you a tidy sum if you get lucky and find a real bargain. However, tickets usually don’t get cheaper closer to the departure date. If you choose to wait, flights could also be booked out or the best seats taken (because who wants the middle seat?). If you don’t want to risk it, book well ahead of the date you want to leave. Don’t forget that some of the biggest bargains can be found up to 12 months in advance. If your favorite carrier hasn’t released its fares yet, check back regularly as deals are constantly updated on Expedia.
What airports do you fly into for Philadelphia from Seattle?
From Seattle, you can get to Philadelphia via Philadelphia Intl. Airport (PHL), Atlantic City Intl. Airport (ACY) and Lehigh Valley Intl. Airport (ABE). Research which airport is right for you before making your decision. If you decide on Philadelphia Intl. Airport (PHL), it’s around 7 mi southwest of downtown. Use the dough you save when booking your ticket with Expedia to enjoy the city’s popular sights, such as Liberty Bell Center and Independence Hall.
What are the most popular departure times for flights from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Airport?
Between 9:00 PM - 10:00 PM is when you’ll find lots of Alaska Airlines flights going from SEA to Philadelphia Intl. Airport (PHL). Our useful tip? Book a flight that departs in the morning. With air traffic yet to build up around airports, your odds of jumping on a delay-free flight are higher.
Can I change the date of my flight from Sea-Tac Airport to PHL?
You can easily make changes to your SEA to Philadelphia Intl. Airport (PHL) ticket via the Expedia Trips portal. But before you begin, read through the rules and conditions in your itinerary to find out what the airline will allow you to do and whether fees apply. Some airlines have a change fee per person, on top of any difference in prices. However, if you booked in the last 24 hours, you may be able to cancel for free and book new flights. You can also take a look at our Customer Service portal for more advice and to connect with our Virtual Agent.

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