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$154+ Cheap flights from Seattle to Philadelphia (SEA - PHL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/3. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — PHL
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
1 adult, Economy
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Philadelphia are usually found in March or January, booked 86 days in advance, depart on a Wednesday or Tuesday and return on a Wednesday

Cheap flight deals from Seattle to Philadelphia

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Philadelphia (PHL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated July 31, 2025.

Round-trip from

$283
(Trip.com)

One-way from

$154
(United Airlines)

Popular in

December

Cheapest in

March

Average price

$462

Good round-trip deal

$342 or less

Good one-way deal

$203 or less
From Seattle/Tacoma Intl to Philadelphia
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One-way flight from Seattle/Tacoma Intl to Philadelphia
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Highest demand for flights based on searches. 6% potential increase in price ($30 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($13 potential savings vs. average RT price).
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Average for round-trip flights in July 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Philadelphia.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to Philadelphia.
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Find flight deals from Seattle to Philadelphia

Cheapest flights from Seattle to Philadelphia
Explore the most affordable flight options available from Seattle to Philadelphia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 31, 2025.

This Trip.com deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:00 amSEA - PHL
1 stop13h 43mMultiple Airlines
Thu 10/27:22 amPHL - SEA
Nonstop5h 56mMultiple Airlines
Deal found 7/31$283
This FlightHub deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/206:41 amSEA - PHL
1 stop19h 13mFrontier
Thu 8/217:15 amPHL - SEA
1 stop10h 25mFrontier
Deal found 7/31$285
This United Airlines deal was found by Cheapflights users on 7/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/257:00 pmSEA - PHL
1 stop7h 35mUnited Airlines
Tue 8/263:40 pmPHL - SEA
1 stop8h 37mUnited Airlines
Deal found 7/30$292
This Southwest deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/56:35 amSEA - PHL
1 stop7h 40mSouthwest
Wed 11/124:55 pmPHL - SEA
1 stop9h 00mSouthwest
Deal found 7/31$296
This Delta deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/187:30 pmSEA - PHL
1 stop7h 15mDelta
Tue 9/306:25 pmPHL - SEA
1 stop8h 29mDelta
Deal found 7/31$297
This American Airlines deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/2111:20 pmSEA - PHL
Nonstop4h 58mAmerican Airlines
Sun 11/236:50 pmPHL - SEA
Nonstop6h 25mAmerican Airlines
Deal found 7/31$317
This Alaska Airlines deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/69:45 amSEA - PHL
Nonstop5h 26mAlaska Airlines
Mon 10/67:11 pmPHL - SEA
Nonstop6h 21mAlaska Airlines
Deal found 7/31$321
This Sun Country Air deal was found by Cheapflights users on 7/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Sun Country Air is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/26:04 pmSEA - PHL
1 stop12h 35mSun Country Air
Sun 10/510:05 amPHL - SEA
1 stop10h 08mSun Country Air
Deal found 7/30$355

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Philadelphia that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 31, 2025.
Use the filters below to find and compare flights from Seattle to Philadelphia that are best for you.

Fly from

Seattle

Fly to

Philadelphia

Route

Depart

Return

Price

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 10/1

7:00 am-11:43 pm

1 stop13h 43m

Philadelphia

Thu 10/2

7:22 am-10:18 am

Nonstop5h 56m

$283

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 9/19

6:12 am-12:57 am

1 stop15h 45m

Philadelphia

Sat 9/20

6:45 am-8:39 pm

1 stop16h 54m

$285

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 8/29

7:00 pm-5:35 am

1 stop7h 35m

Philadelphia

Tue 9/2

6:30 am-1:28 pm

1 stop9h 58m

$292

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Thu 9/18

7:30 pm-5:45 am

1 stop7h 15m

Philadelphia

Tue 9/30

6:25 pm-11:54 pm

1 stop8h 29m

$297

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 10/1

7:45 am-4:05 pm

Nonstop5h 20m

Philadelphia

Thu 10/2

6:50 pm-10:04 pm

Nonstop6h 14m

$318

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Mon 10/6

9:45 am-6:11 pm

Nonstop5h 26m

Philadelphia

Mon 10/6

7:11 pm-10:32 pm

Nonstop6h 21m

$321

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Sat 10/18

5:45 am-3:40 pm

1 stop6h 55m

Philadelphia

Wed 10/22

2:45 pm-11:45 pm

2 stops12h 00m

$330

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Thu 10/2

6:04 pm-9:39 am

1 stop12h 35m

Philadelphia

Sun 10/5

10:05 am-5:13 pm

1 stop10h 08m

$355

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 9/3

11:11 am-12:21 am

2 stops10h 10m

$154

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Sun 9/7

6:12 am-12:57 am

1 stop15h 45m

$157

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/31

Showing 1-10 of 18 results
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The best insider tips for Seattle to Philadelphia flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to Philadelphia trip
Airports
SEA

Plan to arrive at SEA at least two hours before your flight. Use SEA Spot Saver for security screening appointments to save time.

Read more about SEAby Brandon Schultz
PHL

For a quick trip to Center City, take the SEPTA Airport Line. It's efficient and operates from 5:00 a.m. to midnight.

Read more about PHLby Mark Chesnut
Our travel experts
Mark Chesnut

Mark Chesnut

Expert on PHL

Mark Chesnut

Mark Chesnut

Mark Chesnut is a travel writer and public speaker with more than 30 years of experience. The 2019 winner of the NLGJA Excellence in Travel Writing Award, Mark is the author of the book “Prepare for Departure” and has covered air travel for multiple top consumer and trade media outlets.

Read more
Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz

Brandon Schultz

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more

Best time to book a flight from Seattle to Philadelphia

Have a flexible travel schedule? Discover the best time to fly to Philadelphia from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Philadelphia

How far ahead should I book a flight from Seattle to Philadelphia?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Philadelphia. Price data was last updated on July 25, 2025.

The best time to book flights from Seattle to Philadelphia is 86 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from Seattle to Philadelphia?

Currently, August is the cheapest month in which you can book a flight from Seattle to Philadelphia (average of $236). Flying from Seattle to Philadelphia in March is currently the most expensive (average of $295). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SEA to PHL?

Find hourly flight availability from Seattle to Philadelphia. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 31, 2025.

A simple way to save on the total cost of your ticket is to fly from Seattle to Philadelphia at noon. If you’re flexible enough to do this you can expect to save up to 53% on your trip compared to booking a flight in the afternoon.

What is the cheapest day to fly from Seattle to Philadelphia?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Philadelphia. Price data was last updated on July 27, 2025.

Travelers seeking maximum savings on their Seattle to Philadelphia flight should consider departing on Wednesday afternoons when fares are most often at their lowest. Saturday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Seattle to Philadelphia

Explore weekly flight availability from Seattle to Philadelphia. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 31, 2025.

The most flights from SEA to PHL are scheduled on a Thursday (12 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (7 on average).

Reviews of airlines servicing Philadelphia

Get insights into the airlines that provide service to Philadelphia. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Philadelphia. Reviews last updated July 31, 2025.
Peruse reviews from past customers who have flown with Alaska Airlines, Southwest, and Delta from Seattle to Philadelphia to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Southwest
8.0
Very good
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,981 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,900 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Philadelphia. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airports do I use to fly from Seattle to Philadelphia?

    To fly from Seattle to Philadelphia, you need to book a flight from Seattle/Tacoma Intl (SEA) to Philadelphia (PHL). Nonstop flights to Philadelphia from Seattle/Tacoma Intl take 5h 05m on average. When it comes time to book airfare, you have a few options: there are 9 outbound flights from Seattle/Tacoma Intl to Philadelphia offered by 9 different airlines.

  • How popular is this Seattle to Philadelphia flight route?

    Flights from Seattle/Tacoma Intl to Philadelphia have been viewed 13 times in the past calendar month.

  • What are the cheapest airlines flying from Seattle to Philadelphia round-trip?

    Currently priced at $285, Frontier will fly you from Seattle to Philadelphia and back. In addition to Frontier, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from United Airlines and Southwest - these airlines can fly you to your destination from $292 and $296, respectively. Frontier is currently priced 36% below the average price you’ll pay for this route.

  • What are the cheapest airlines to fly from Seattle to Philadelphia one-way?

    One-way options have recently been found by users for as low as $154 on United Airlines. Other airlines that offer cheap prices include Delta from $157 and American Airlines from $159 one-way.

  • What are the most reliable airlines from Seattle to Philadelphia?

    No one likes to see their flight delayed. When booking a flight from Seattle to Philadelphia consider choosing American Airlines (77%), Hawaiian Airlines (68%) or Air Tahiti Nui (68%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Seattle to Philadelphia?

    Looking at all options, your cheapest flight can be booked for $138. While the most popular route (Seattle/Tacoma Intl - Philadelphia) can be booked for $265 on average our data indicates $629 when flying from Seattle to Philadelphia.

  • Can I find deals for flights from Seattle to Philadelphia that include hotel bookings?

    Yes. In addition to deals on Seattle to Philadelphia flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Philadelphia?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Philadelphia.

  • Can I find deals for business class flights from Seattle to Philadelphia?

    Yes. Cheapflights offers flight deals from Seattle to Philadelphia by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to Philadelphia?

    Currently, August is the cheapest month in which you can book a flight from Seattle to Philadelphia (average of $236). Flying from Seattle to Philadelphia in March is currently the most expensive (average of $295). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Philadelphia?

Book flights to Philadelphia if you plan to visit one of these locations
Vineland
Wildwood
King of Prussia
Pottstown
Cherry Hill
Ocean City
Chester
Millville
Reading
Ephrata
Camden
Dewey Beach
Dover
Elkton
Essington
Willow Grove
Newark
Exton
Glen Mills
Springfield

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Seattle to Philadelphia

See prices for flight routes from nearby airports that may be better suited for you.
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Top 9 airlines flying from Seattle to Philadelphia

Discover the top 9 airlines that operate flights from Seattle to Philadelphia. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$113Average$249FlexibilityNo cancel feeOn-time65%
FrontierCheapest$132Average$282FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$256Average$414FlexibilityNo cancel feeOn-time69%
DeltaCheapest$276Average$383FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$291Average$541FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$296Average$425FlexibilityNo cancel feeOn-time71%
Sun Country AirCheapest$311Average$480FlexibilityNo cancel feeOn-time83%
Hawaiian AirlinesCheapest$327Average$549FlexibilityNo cancel feeOn-time85%
SouthwestCheapest$349Average$432FlexibilityNo cancel feeOn-time63%

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