$138 Cheap Flights from Seattle (SEA) to Philadelphia (PHL)

View $138 flight on Wed, Dec 3, 2025Opens in a new window

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

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Cheap Flights from Seattle to Philadelphia (SEA-PHL)

Prices were available within the past 7 days and start at $138 for one-way flights and $271 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Tue, Oct 28 - Wed, Oct 29
SEA
Seattle
PHL
Philadelphia
$271 Roundtrip, found 4 hours ago
$271
Roundtrip
found 4 hours ago
Select Alaska Airlines flight, departing Tue, Oct 28 from Seattle to Philadelphia, returning Wed, Oct 29, priced at $271 found 4 hours ago
Alaska Airlines
Wed, Aug 27 - Sat, Aug 30
SEA
Seattle
PHL
Philadelphia
$273 Roundtrip, just found
$273
Roundtrip
just found
Select Alaska Airlines flight, departing Wed, Aug 27 from Seattle to Philadelphia, returning Sat, Aug 30, priced at $273 just found
Alaska Airlines
Wed, Aug 27 - Tue, Sep 2
SEA
Seattle
PHL
Philadelphia
$277 Roundtrip, just found
$277
Roundtrip
just found
Select Alaska Airlines flight, departing Wed, Aug 27 from Seattle to Philadelphia, returning Tue, Sep 2, priced at $277 just found
American Airlines
Thu, Nov 20 - Sat, Nov 22
SEA
Seattle
PHL
Philadelphia
$277 Roundtrip, just found
$277
Roundtrip
just found
Select American Airlines flight, departing Thu, Nov 20 from Seattle to Philadelphia, returning Sat, Nov 22, priced at $277 just found
United
Wed, Aug 27 - Sat, Aug 30
SEA
Seattle
PHL
Philadelphia
$278 Roundtrip, just found
$278
Roundtrip
just found
Select United flight, departing Wed, Aug 27 from Seattle to Philadelphia, returning Sat, Aug 30, priced at $278 just found
Alaska Airlines
Sat, Oct 25 - Tue, Oct 28
SEA
Seattle
PHL
Philadelphia
$280 Roundtrip, just found
$280
Roundtrip
just found
Select Alaska Airlines flight, departing Sat, Oct 25 from Seattle to Philadelphia, returning Tue, Oct 28, priced at $280 just found
Alaska Airlines
Wed, Aug 27 - Tue, Sep 2
SEA
Seattle
PHL
Philadelphia
$282 Roundtrip, just found
$282
Roundtrip
just found
Select Alaska Airlines flight, departing Wed, Aug 27 from Seattle to Philadelphia, returning Tue, Sep 2, priced at $282 just found
American Airlines
Wed, Oct 29 - Fri, Oct 31
SEA
Seattle
PHL
Philadelphia
$282 Roundtrip, just found
$282
Roundtrip
just found
Select American Airlines flight, departing Wed, Oct 29 from Seattle to Philadelphia, returning Fri, Oct 31, priced at $282 just found
Frontier Airlines
Fri, Aug 29 - Sat, Aug 30
SEA
Seattle
PHL
Philadelphia
$283 Roundtrip, found 4 hours ago
$283
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Fri, Aug 29 from Seattle to Philadelphia, returning Sat, Aug 30, priced at $283 found 4 hours ago
Southwest Airlines
Tue, Sep 23 - Fri, Sep 26
SEA
Seattle
PHL
Philadelphia
$287 Roundtrip, just found
$287
Roundtrip
just found
Select Southwest Airlines flight, departing Tue, Sep 23 from Seattle to Philadelphia, returning Fri, Sep 26, priced at $287 just found

Find the cheapest month to fly from Seattle (SEA) to Philadelphia (PHL)

September is typically the cheapest month to fly

From $137 - $266 per traveler.

Graph displaying average flight prices per month

Alternative airports near Philadelphia

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to New Castle ILG. Average driving time to city center is 44 minutes. Flights from $531
ILG
New Castle
Average driving time to city center44 min
Flights from $531
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, JetBlue Airways, Southwest Airlines, Spirit Airlines, Sun Country Airlines, United
Roundtrip price
$267
Distance
2371 mi
Average flight time
8 hours 50 mins

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 October. 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 $138 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 much does a flight from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) cost?
Score cheap return fares from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) starting from $269. Reserve your seat and be on your way. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Alaska Airlines flight leaving SEA on August 15 2025 and touching down at PHL. The price was last updated on July 23 2025 and has not changed since.
What is the cheapest month to fly from SEA to PHL?
The cheapest flights from SEA to PHL are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
You can fly nonstop from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) on an Alaska Airlines flight.
What is the cheapest airline that flies from SEA to PHL?
Currently, the cheapest carrier operating one-way flights from SEA to PHL is Alaska Airlines. You can book a seat on this route from $137. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from SEA on September 4 2025. Prices were last updated on July 23 2025 and have not changed since.
How many flights per day from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
On average, you can pick from 6 direct flights each week from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL). To expand your choices, consider a flight with a layover. Just enter your details on Expedia and then set the filter tool to include one or more stops.
What are the most popular departure times for flights from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
More passengers fly between SEA and PHL at 9 AM than at any other time of day. Looking for a quieter experience? Travel outside of rush hours and you're likely to save on your fare as well.
What day of the week has the most flights from SEA to PHL?
Friday offers the most flights from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL). Consider leaving on this day and you'll have a greater chance of finding a departure that fits your schedule.
What is the earliest flight from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
The earliest flight out of Seattle - Tacoma Intl. Airport (SEA) is at around 9:15AM UTC-8. Catch this flight and you'll reach Philadelphia Intl. Airport (PHL) at approximately 5:32PM UTC-5. The total time in the air is 5h 17m.
How long does it take to fly from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
Flights from SEA to PHL have an average travel time of 5 hours and 17 minutes. The total distance between the two airports is 2,400 mi.
What airline has the least delays from SEA to PHL?
American Airlines has the best track record for on-time direct flights from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL), with an on-time score of 82%. Use the Expedia App to see your flight status before you take off and receive notifications about any trip changes.
What is the best time to fly from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
To avoid potential delays on the Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) route, aim to travel before 3 PM. Departures after this hour have a 22% higher chance of cancellation.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for Philadelphia from Seattle - Tacoma Intl. Airport (SEA)?
Check out your flight options from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL). This is the only airport in Philadelphia you can fly into if you're taking a direct flight.
Is it cheaper to buy a plane ticket from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL) last-minute?
Last-minute fares from SEA to PHL are usually more expensive. For the best prices, start searching for flights well ahead of time. That being said, if you can play around with your travel dates, it's possible to find a cheap fare just before your departure.
Is it cheaper to book a SEA to PHL flight and hotel package?
Securing a SEA to PHL flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your travels in one place. Pick from our extensive range of hotels and then add car rentals, flights and activities to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Seattle - Tacoma Intl. Airport (SEA) to Philadelphia Intl. Airport (PHL)?
In most cases, you can modify or cancel your SEA to PHL flight. However, additional charges may apply, especially if your booking was made more than 24 hours ago. Double-check your itinerary for the airline's policies and fees on flight changes, or if you need further information, head to our Customer Service portal.

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