HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Philadelphia

$148+ 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 8/12. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — PHL
Jul 8 — Jul 151
Tue 7/8
Tue 7/15
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Seattle to Philadelphia with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Philadelphia are usually found in March or January, booked 85 days in advance, depart on a Tuesday or Wednesday 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 3, 2025.

Round-trip from

$312
(Southwest)

One-way from

$148
(Southwest)

Popular in

December

Cheapest in

March

Average price

$461

Good round-trip deal

$385 or less

Good one-way deal

$190 or less
From Seattle/Tacoma Intl to Philadelphia
Search Deals
One-way flight from Seattle/Tacoma Intl to Philadelphia
Search Deals
Highest demand for flights based on searches. 6% potential increase in price ($29 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($12 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2025
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to Philadelphia.
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to Philadelphia.
Search Deals

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 3, 2025.

This Southwest deal was found by Cheapflights users on 7/2. 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 9/310:10 amSEA - PHL
1 stop8h 40mSouthwest
Wed 9/107:45 amPHL - SEA
2 stops10h 25mSouthwest
Deal found 7/2$312
This Delta deal was found by Cheapflights users on 7/1. 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.
Wed 8/65:45 pmSEA - PHL
1 stop9h 05mDelta
Mon 8/116:59 pmPHL - SEA
1 stop7h 48mDelta
Deal found 7/1$313
This FlightHub deal was found by Cheapflights users on 7/3. 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.
Fri 8/15:30 pmSEA - PHL
2 stops12h 53mMultiple Airlines
Sat 8/166:15 amPHL - SEA
1 stop20h 27mMultiple Airlines
Deal found 7/3$314
This FlightHub deal was found by Cheapflights users on 7/3. 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.
Tue 7/226:25 amSEA - PHL
1 stop19h 44mFrontier
Tue 7/296:15 amPHL - SEA
1 stop20h 27mFrontier
Deal found 7/3$315
This American Airlines deal was found by Cheapflights users on 7/3. 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.
Wed 8/1310:50 pmSEA - PHL
Nonstop5h 10mAmerican Airlines
Sun 8/177:10 pmPHL - SEA
Nonstop6h 16mAmerican Airlines
Deal found 7/3$317
This Alaska Airlines deal was found by Cheapflights users on 7/1. 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.
Wed 8/69:15 pmSEA - PHL
Nonstop5h 10mAlaska Airlines
Thu 8/146:52 pmPHL - SEA
Nonstop6h 05mAlaska Airlines
Deal found 7/1$337
This Mytrip deal was found by Cheapflights users on 6/30. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/285:30 pmSEA - PHL
3 stops26h 51mSpirit Airlines
Tue 8/59:15 pmPHL - SEA
2 stops22h 10mSpirit Airlines
Deal found 6/30$345
This Sun Country Air deal was found by Cheapflights users on 7/3. 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 11/206:24 pmSEA - PHL
1 stop12h 27mSun Country Air
Sun 11/2310:00 amPHL - SEA
1 stop10h 15mSun Country Air
Deal found 7/3$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 3, 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 9/3

10:10 am-9:50 pm

1 stop8h 40m

Philadelphia

Wed 9/10

7:45 am-3:10 pm

2 stops10h 25m

$312

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 8/6

5:45 pm-5:50 am

1 stop9h 05m

Philadelphia

Sun 8/10

5:30 am-12:09 pm

1 stop9h 39m

$313

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 8/1

5:30 pm-9:23 am

2 stops12h 53m

Philadelphia

Sat 8/16

6:15 am-11:42 pm

1 stop20h 27m

$314

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Tue 7/22

6:25 am-5:09 am

1 stop19h 44m

Philadelphia

Tue 7/29

6:15 am-11:42 pm

1 stop20h 27m

$315

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 8/13

10:50 pm-7:00 am

Nonstop5h 10m

Philadelphia

Sun 8/17

7:10 pm-10:26 pm

Nonstop6h 16m

$317

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 8/6

9:15 pm-5:25 am

Nonstop5h 10m

Philadelphia

Thu 8/14

6:52 pm-9:57 pm

Nonstop6h 05m

$337

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Mon 7/28

5:30 pm-11:21 pm

3 stops26h 51m

Philadelphia

Tue 8/5

9:15 pm-4:25 pm

2 stops22h 10m

$345

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Thu 11/20

6:24 pm-9:51 am

1 stop12h 27m

Philadelphia

Sun 11/23

10:00 am-5:15 pm

1 stop10h 15m

$355

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Tue 8/12

5:35 am-4:00 pm

1 stop7h 25m

$148

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 8/13

5:30 am-5:45 pm

1 stop9h 15m

$149

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/1

Showing 1-10 of 16 results
1
2

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 June 27, 2025.

The best time to book flights from Seattle to Philadelphia is 85 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 3, 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 June 29, 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 3, 2025.

The most flights from SEA to PHL are scheduled on a Thursday (12 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (5 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 3, 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

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Southwest
8.0
Very good
4,266 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Delta
8.0
Very good
7,982 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
United Airlines
7.4
Good
8,861 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥

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 07m on average. When it comes time to book airfare, you have a few options: there are 8 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 14 times in the past calendar month.

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

    Currently priced at $312, Southwest will fly you from Seattle to Philadelphia and back. In addition to Southwest, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Delta and Frontier - these airlines can fly you to your destination from $313 and $315, respectively. Southwest is currently priced 30% 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 $148 on Southwest. Other airlines that offer cheap prices include Delta from $149 and Frontier from $150 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 (75%), Hawaiian Airlines (63%) or Air Tahiti Nui (63%) 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 $239 on average our data indicates $1,583 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 Seattle?

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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Seattle to Philadelphia

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to John F Kennedy Intl flights
Seattle to Newark flights
Seattle to LaGuardia flights
Portland to John F Kennedy Intl flights
Portland to Newark flights
Seattle to Dulles Intl flights
Seattle to Reagan-National flights
Portland to LaGuardia flights
Portland to Reagan-National flights
Portland to Dulles Intl flights
Seattle to Pittsburgh flights
Portland to Philadelphia flights
Portland to Pittsburgh flights
Spokane to John F Kennedy Intl flights
Spokane to Newark flights
Spokane to Reagan-National flights
Spokane to LaGuardia flights
Spokane to Dulles Intl flights
Seattle to Harrisburg flights
Pasco to John F Kennedy Intl flights
Seattle to State College flights
Portland to Harrisburg flights
Seattle to Allentown flights
Portland to State College flights
Wenatchee to Dulles Intl flights
Pasco to Newark flights
Wenatchee to Reagan-National flights
Pasco to LaGuardia flights
Spokane to Pittsburgh flights
Spokane to Philadelphia flights
Pasco to Dulles Intl flights
Pasco to Philadelphia flights
Bellingham to John F Kennedy Intl flights
Pullman to Newark flights
Seattle to Scranton flights
Bellingham to Newark flights
Seattle to Elmira flights
Pullman to John F Kennedy Intl flights
Spokane to Harrisburg flights
Pasco to Pittsburgh flights
Pasco to Reagan-National flights
Wenatchee to Philadelphia flights
Bellingham to Dulles Intl flights
Spokane to Scranton flights
Bellingham to LaGuardia flights
Portland to Elmira flights
Portland to Allentown flights
Bellingham to Reagan-National flights
Walla Walla to John F Kennedy Intl flights

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 3, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$113Average$233FlexibilityNo cancel feeOn-time65%
FrontierCheapest$138Average$284FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$256Average$414FlexibilityNo cancel feeOn-time69%
DeltaCheapest$276Average$387FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$296Average$540FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$297Average$431FlexibilityNo cancel feeOn-time71%
Sun Country AirCheapest$311Average$420FlexibilityNo cancel feeOn-time83%
Hawaiian AirlinesCheapest$327Average$555FlexibilityNo cancel feeOn-time85%
SouthwestCheapest$346Average$427FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.