$95 Cheap Flights from St. Louis (STL) to Philadelphia (PHL)

View $95 flight on Wed, Sep 3, 2025Opens in a new window

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Cheap Flights from St. Louis to Philadelphia (STL-PHL)

Prices were available within the past 7 days and start at $95 for one-way flights and $167 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Spirit Airlines
Mon, Aug 25 - Sun, Aug 31
STL
St. Louis
PHL
Philadelphia
$167 Roundtrip, found 5 days ago
$167
Roundtrip
found 5 days ago
Select Spirit Airlines flight, departing Mon, Aug 25 from St. Louis to Philadelphia, returning Sun, Aug 31, priced at $167 found 5 days ago
Spirit Airlines
Sun, Aug 31 - Tue, Sep 2
STL
St. Louis
PHL
Philadelphia
$184 Roundtrip, found 5 days ago
$184
Roundtrip
found 5 days ago
Select Spirit Airlines flight, departing Sun, Aug 31 from St. Louis to Philadelphia, returning Tue, Sep 2, priced at $184 found 5 days ago
Southwest Airlines
Tue, Oct 28 - Wed, Oct 29
STL
St. Louis
PHL
Philadelphia
$189 Roundtrip, found 6 hours ago
$189
Roundtrip
found 6 hours ago
Select Southwest Airlines flight, departing Tue, Oct 28 from St. Louis to Philadelphia, returning Wed, Oct 29, priced at $189 found 6 hours ago
American Airlines
Tue, Oct 28 - Wed, Oct 29
STL
St. Louis
PHL
Philadelphia
$189 Roundtrip, found 6 hours ago
$189
Roundtrip
found 6 hours ago
Select American Airlines flight, departing Tue, Oct 28 from St. Louis to Philadelphia, returning Wed, Oct 29, priced at $189 found 6 hours ago
Frontier Airlines
Sat, Aug 16 - Mon, Aug 25
STL
St. Louis
PHL
Philadelphia
$191 Roundtrip, found 6 days ago
$191
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Sat, Aug 16 from St. Louis to Philadelphia, returning Mon, Aug 25, priced at $191 found 6 days ago
Southwest Airlines
Wed, Sep 3 - Sat, Sep 6
STL
St. Louis
PHL
Philadelphia
$191 Roundtrip, found 6 hours ago
$191
Roundtrip
found 6 hours ago
Select Southwest Airlines flight, departing Wed, Sep 3 from St. Louis to Philadelphia, returning Sat, Sep 6, priced at $191 found 6 hours ago
Southwest Airlines
Wed, Oct 15 - Mon, Oct 20
STL
St. Louis
PHL
Philadelphia
$193 Roundtrip, found 15 hours ago
$193
Roundtrip
found 15 hours ago
Select Southwest Airlines flight, departing Wed, Oct 15 from St. Louis to Philadelphia, returning Mon, Oct 20, priced at $193 found 15 hours ago
Frontier Airlines
Sat, Aug 23 - Sun, Aug 31
STL
St. Louis
PHL
Philadelphia
$194 Roundtrip, found 5 days ago
$194
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Sat, Aug 23 from St. Louis to Philadelphia, returning Sun, Aug 31, priced at $194 found 5 days ago
Spirit Airlines
Thu, Sep 18 - Sat, Sep 20
STL
St. Louis
PHL
Philadelphia
$195 Roundtrip, found 1 day ago
$195
Roundtrip
found 1 day ago
Select Spirit Airlines flight, departing Thu, Sep 18 from St. Louis to Philadelphia, returning Sat, Sep 20, priced at $195 found 1 day ago
United
Tue, Oct 28 - Wed, Oct 29
STL
St. Louis
PHL
Philadelphia
$201 Roundtrip, found 6 hours ago
$201
Roundtrip
found 6 hours ago
Select United flight, departing Tue, Oct 28 from St. Louis to Philadelphia, returning Wed, Oct 29, priced at $201 found 6 hours ago
Flights from St. Louis (STL) to Philadelphia (PHL)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Philadelphia Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Roundtrip price
$167
Distance
811 mi
Average flight time
3 hours 15 mins

St. Louis to Philadelphia Flights

The cheapest times to fly from St. Louis 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 St. Louis to Philadelphia are during the month of August. You can find some of the cheapest flights from St. Louis to Philadelphia with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Philadelphia

Sunday is one of the best days to book for cheap flights from St. Louis 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 St. Louis 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 St. Louis to Philadelphia in 2025. You can also book with separate airlines for your outbound and return journeys, from $95 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 St. Louis 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 St. Louis 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 Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) cost?
Get a cheap one-way flight from $95 or cheap return flight from $167 from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight deals on this route.
What is the cheapest month to fly from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
August is the cheapest month to fly from STL to PHL. Traveling outside of peak seasons is often the key to finding better deals on flights.
Which airlines fly direct from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
When heading out of Lambert-St. Louis Intl. Airport (STL), you can take a nonstop flight to Philadelphia Intl. Airport (PHL) with American Airlines.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Southwest Airlines and American Airlines are well-known airlines offering competitive fares. Don't forget that flight prices from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) can vary depending on departure dates, demand and how early you book. With Expedia's filter tool, you can easily find a STL to PHL flight that matches your preferences and budget.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
With, on average, 2 nonstop flights departing from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) each day, you'll be taking off on vacation soon enough.
What are the most popular departure times for flights from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
More travelers fly between STL and PHL at 6 AM than at any other point in the day. Rather skip the crowds? Try choosing a quieter departure window and it's possible you'll save on your fare as well.
What day of the week has the most flights from STL to PHL?
If you jet off on a Friday, you'll get the largest range of choices for flights from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL).
What is the earliest flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Lambert-St. Louis Intl. Airport (STL)'s first flight to Philadelphia Intl. Airport (PHL) departs at approximately 6:00AM UTC-6. With a travel time of 2h 10m, you'll arrive at around 9:10AM UTC-5.
How long does it take to fly from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Flights from STL to PHL have an average travel time of 2 hours and 9 minutes. The total distance between these two airports is 810 mi.
What airline has the least delays from STL to PHL?
With 82% of flights usually arriving as scheduled, American Airlines has the best on-time performance for nonstop flights from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL). To check your flight status and get notified about any changes, use the Expedia App.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Opt for a flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) that takes off before 3 PM to reduce the risk of cancellations. Departures after this time have a 22% higher chance of being canceled, on average.**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 Lambert-St. Louis Intl. Airport (STL)?
If you're taking a direct flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia, Philadelphia Intl. Airport (PHL) is the only airport you can touch down at.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) last-minute?
Holding off until just before your departure to book a ticket from STL to PHL generally means paying more. Although you may find some last-minute discounts, there's no guarantee. Keep your travel plans flexible to maximize your chances of snagging a bargain.
Is it cheaper to book a STL to PHL flight and hotel package?
You'll generally save money by securing a STL to PHL flight and hotel package compared to booking separately. In fact, you could save hundreds of dollars by bundling with Expedia. And it's easy to manage it all in one place. Once you've chosen your ideal flights and accommodations, consider adding extras including tours, activities and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
In most cases, you can modify or cancel your STL to PHL flight. However, there may be additional fees, especially if your booking was made more than 24 hours ago. Double-check your itinerary for the airline's fees and policies on flight changes, or if you'd like further details, visit our Customer Service portal.

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