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

View $138 flight on Wed, Oct 15, 2025Opens in a new window

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

Cheap Flights from Philadelphia to Seattle (PHL-SEA)

Prices were available within the past 7 days and start at $138 for one-way flights and $243 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Southwest Airlines
Tue, Nov 18 - Tue, Nov 25
PHL
Philadelphia
SEA
Seattle
$243 Roundtrip, found 5 days ago
$243
Roundtrip
found 5 days ago
Select Southwest Airlines flight, departing Tue, Nov 18 from Philadelphia to Seattle, returning Tue, Nov 25, priced at $243 found 5 days ago
Bargain Flight
Fri, Oct 3 - Thu, Oct 9
PHL
Philadelphia
SEA
Seattle
$274 Roundtrip, just found
$274
Roundtrip
just found
Select Bargain Flight flight, departing Fri, Oct 3 from Philadelphia to Seattle, returning Thu, Oct 9, priced at $274 just found
Hawaiian Airlines
Tue, Sep 16 - Sun, Oct 5
PHL
Philadelphia
SEA
Seattle
$277 Roundtrip, found 1 day ago
$277
Roundtrip
found 1 day ago
Select Hawaiian Airlines flight, departing Tue, Sep 16 from Philadelphia to Seattle, returning Sun, Oct 5, priced at $277 found 1 day ago
American Airlines
Sun, Oct 12 - Sat, Oct 18
PHL
Philadelphia
SEA
Seattle
$277 Roundtrip, just found
$277
Roundtrip
just found
Select American Airlines flight, departing Sun, Oct 12 from Philadelphia to Seattle, returning Sat, Oct 18, priced at $277 just found
Bargain Flight
Mon, Nov 10 - Thu, Nov 27
PHL
Philadelphia
SEA
Seattle
$278 Roundtrip, found 3 hours ago
$278
Roundtrip
found 3 hours ago
Select Bargain Flight flight, departing Mon, Nov 10 from Philadelphia to Seattle, returning Thu, Nov 27, priced at $278 found 3 hours ago
Alaska Airlines
Sun, Oct 12 - Sat, Oct 18
PHL
Philadelphia
SEA
Seattle
$280 Roundtrip, just found
$280
Roundtrip
just found
Select Alaska Airlines flight, departing Sun, Oct 12 from Philadelphia to Seattle, returning Sat, Oct 18, priced at $280 just found
Alaska Airlines
Thu, Sep 11 - Sat, Sep 13
PHL
Philadelphia
SEA
Seattle
$281 Roundtrip, just found
$281
Roundtrip
just found
Select Alaska Airlines flight, departing Thu, Sep 11 from Philadelphia to Seattle, returning Sat, Sep 13, priced at $281 just found
Alaska Airlines
Mon, Nov 10 - Thu, Nov 27
PHL
Philadelphia
SEA
Seattle
$282 Roundtrip, found 3 hours ago
$282
Roundtrip
found 3 hours ago
Select Alaska Airlines flight, departing Mon, Nov 10 from Philadelphia to Seattle, returning Thu, Nov 27, priced at $282 found 3 hours ago
Alaska Airlines
Mon, Nov 10 - Thu, Nov 27
PHL
Philadelphia
SEA
Seattle
$285 Roundtrip, found 3 hours ago
$285
Roundtrip
found 3 hours ago
Select Alaska Airlines flight, departing Mon, Nov 10 from Philadelphia to Seattle, returning Thu, Nov 27, priced at $285 found 3 hours ago
Alaska Airlines
Mon, Aug 18 - Wed, Aug 20
PHL
Philadelphia
SEA
Seattle
$286 Roundtrip, just found
$286
Roundtrip
just found
Select Alaska Airlines flight, departing Mon, Aug 18 from Philadelphia to Seattle, returning Wed, Aug 20, priced at $286 just found

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

September is typically the cheapest month to fly

From $138 - $273 per traveler.

Graph displaying average flight prices per month

Flights from Philadelphia (PHL) to Seattle (SEA)
Origin airport
Philadelphia Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, JetBlue Airways, Southwest Airlines, Spirit Airlines, Sun Country Airlines, United
Roundtrip price
$243
Distance
2371 mi
Average flight time
3 hours 48 mins

Philadelphia to Seattle Flights

The cheapest times to fly from Philadelphia to Seattle

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 Philadelphia to Seattle are during the month of November. You can find some of the cheapest flights from Philadelphia to Seattle with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Philadelphia to Seattle

Sunday is one of the best days to book for cheap flights from Philadelphia to Seattle: 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 Philadelphia to Seattle

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 Philadelphia to Seattle 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 Philadelphia to Seattle 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 Philadelphia to Seattle 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 Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA) cost?
Cheap round-trip fares from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA) start from $274. 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 PHL on August 4 2025 and touching down at SEA. The price was last updated on July 14 2025 and has not changed since.
What is the cheapest month to fly from PHL to SEA?
The cheapest flights from PHL to SEA 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 Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
When heading out of Philadelphia Intl. Airport (PHL), you can get on a nonstop flight to Seattle - Tacoma Intl. Airport (SEA) with Alaska Airlines.
What is the cheapest airline that flies from PHL to SEA?
Travel from PHL to SEA with Alaska Airlines. This airline currently offers the cheapest one-way ticket for this route, starting at $137. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from PHL on October 7 2025. Prices were last updated on July 14 2025 and have not changed since.
How many flights per day from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
On average, you can pick from 6 direct flights per week from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA). For more options, consider flights with layovers. Simply enter your details on Expedia and then set the filters to include one or more stops.
What are the most popular departure times for flights from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
The 6 PM departures from PHL to SEA are the busiest. They can also be more expensive. If you're hoping to save money, pick a less crowded time to fly.
What day of the week has the most flights from PHL to SEA?
Jet off on a Friday if you're searching for the best choice of flights from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA).
What is the earliest flight from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
Take the earliest flight at around 6:32PM UTC-5, departing from Philadelphia Intl. Airport (PHL). You'll be in the air for around 6h 23m, coming in to land at Seattle - Tacoma Intl. Airport (SEA) at approximately 9:55PM UTC-8.
How long does it take to fly from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
Flights from PHL to SEA have an average travel time of 6 hours and 23 minutes. The total distance between the two is 2,400 mi.
What is the best time to fly from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
Choose a flight from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA) that leaves before 3 PM to reduce the risk of cancellations. Departures after this hour are on average 22% more likely to be canceled.**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 Seattle from Philadelphia Intl. Airport (PHL)?
If you're traveling on a direct flight from Philadelphia Intl. Airport (PHL) to Seattle, Seattle - Tacoma Intl. Airport (SEA) is the only airport you can land at.
Is it cheaper to buy a plane ticket from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA) last-minute?
Booking your plane ticket from PHL to SEA shortly before your getaway is typically more expensive. But if there's some wiggle room with your departure dates and times, you could snag a cheap last-minute fare.
Is it cheaper to book a PHL to SEA flight and hotel package?
You can save money by booking a PHL to SEA flight and hotel package compared to booking separately. In fact, travelers could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one place. Once you've selected your preferred accommodations and flights, consider adding extras like car rentals, activities and tours.
Can I cancel or change the date of my flight from Philadelphia Intl. Airport (PHL) to Seattle - Tacoma Intl. Airport (SEA)?
In most instances, you can reschedule or cancel your PHL to SEA 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 guidelines and fees on flight changes, or if you'd like further information, go to our Customer Service portal.

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*Available to One Key members.