$69 Cheap Flights from Philadelphia (PHL) to St. Louis (STL)

View $69 flight on Mon, Feb 2, 2026Opens in a new window

Popular airlines from Philadelphia Intl. Airport (PHL) to St. Louis Lambert Intl. Airport (STL)

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

Prices were available within the past 7 days and start at $69 for one-way flights and $128 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Mon, Jan 26 - Fri, Jan 30
PHL
Philadelphia
STL
St. Louis
$128 Roundtrip, found 1 day ago
$128
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Mon, Jan 26 from Philadelphia to St. Louis, returning Fri, Jan 30, priced at $128 found 1 day ago
Frontier Airlines
Mon, Jan 26 - Fri, Jan 30
PHL
Philadelphia
STL
St. Louis
$145 Roundtrip, found 1 day ago
$145
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Mon, Jan 26 from Philadelphia to St. Louis, returning Fri, Jan 30, priced at $145 found 1 day ago
Frontier Airlines
Thu, Jan 8 - Mon, Jan 12
PHL
Philadelphia
STL
St. Louis
$162 Roundtrip, just found
$162
Roundtrip
just found
Select Frontier Airlines flight, departing Thu, Jan 8 from Philadelphia to St. Louis, returning Mon, Jan 12, priced at $162 just found
Frontier Airlines
Sun, Dec 21 - Tue, Dec 30
PHL
Philadelphia
STL
St. Louis
$163 Roundtrip, found 1 day ago
$163
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Sun, Dec 21 from Philadelphia to St. Louis, returning Tue, Dec 30, priced at $163 found 1 day ago
Frontier Airlines
Sat, Dec 20 - Wed, Dec 31
PHL
Philadelphia
STL
St. Louis
$164 Roundtrip, found 1 day ago
$164
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Sat, Dec 20 from Philadelphia to St. Louis, returning Wed, Dec 31, priced at $164 found 1 day ago
Frontier Airlines
Sun, Jan 25 - Tue, Jan 27
PHL
Philadelphia
STL
St. Louis
$166 Roundtrip, found 4 hours ago
$166
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Sun, Jan 25 from Philadelphia to St. Louis, returning Tue, Jan 27, priced at $166 found 4 hours ago
Southwest Airlines
Wed, Jan 28 - Sat, Jan 31
PHL
Philadelphia
STL
St. Louis
$171 Roundtrip, found 21 hours ago
$171
Roundtrip
found 21 hours ago
Select Southwest Airlines flight, departing Wed, Jan 28 from Philadelphia to St. Louis, returning Sat, Jan 31, priced at $171 found 21 hours ago
American Airlines
Wed, Mar 4 - Sat, Mar 7
PHL
Philadelphia
STL
St. Louis
$172 Roundtrip, found 1 hour ago
$172
Roundtrip
found 1 hour ago
Select American Airlines flight, departing Wed, Mar 4 from Philadelphia to St. Louis, returning Sat, Mar 7, priced at $172 found 1 hour ago
Delta
Wed, Jan 28 - Sat, Jan 31
PHL
Philadelphia
STL
St. Louis
$180 Roundtrip, found 21 hours ago
$180
Roundtrip
found 21 hours ago
Select Delta flight, departing Wed, Jan 28 from Philadelphia to St. Louis, returning Sat, Jan 31, priced at $180 found 21 hours ago
United
Tue, Feb 17 - Tue, Feb 24
PHL
Philadelphia
STL
St. Louis
$211 Roundtrip, found 2 days ago
$211
Roundtrip
found 2 days ago
Select United flight, departing Tue, Feb 17 from Philadelphia to St. Louis, returning Tue, Feb 24, priced at $211 found 2 days ago

Find the cheapest month to fly from Philadelphia (PHL) to St. Louis (STL)

February is typically the cheapest month to fly

From $120 - $387 per traveler.

Alternative airports near St. Louis

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

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $282
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $282
Flights from Philadelphia (PHL) to St. Louis (STL)
Origin airport
Philadelphia Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Roundtrip price
$128
Distance
811 mi
Average flight time
1 hour 35 mins

Philadelphia to St. Louis Flights

The cheapest times to fly from Philadelphia to St. Louis

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

 

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

Sunday is one of the best days to book for cheap flights from Philadelphia to St. Louis: 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 St. Louis

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 St. Louis in 2026. You can also book with separate airlines for your outbound and return journeys, from $69 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 St. Louis 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 St. Louis 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 Lambert-St. Louis Intl. Airport (STL) cost?
Snag a cheap one-way flight from $69 or cheap return flight from $128 from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL) 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 Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
Traveling in January is a good way to save, as it's the cheapest month for flights between PHL and STL. You'll often find the lowest prices during off-peak months.
Which airlines fly direct from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
Take a direct flight with American Airlines and head straight from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL).
What is the cheapest airline that flies from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
While prices may vary depending on when you travel, Southwest Airlines and American Airlines are popular options for flights between Philadelphia Intl. Airport (PHL) and Lambert-St. Louis Intl. Airport (STL). You can also compare carriers on Expedia and use the "Sort by" filter to find the cheapest fare for your PHL to STL flight.
How many flights per day from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
With, on average, 2 direct flights departing from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL) each day, you'll be on your way in no time.
What are the most popular departure times for flights from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
More travelers fly between PHL and STL at 11 AM than at any other time of day. Looking to skip the crowds? Pick a flight outside the busiest times and you're likely to save on your fare as well.
What day of the week has the most flights from PHL to STL?
Depart on a Friday if you're searching for the largest selection of flights from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL).
What is the earliest flight from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
The first flight of the day leaving Philadelphia Intl. Airport (PHL) is at around 7:20AM UTC-5. Board this plane and you'll reach Lambert-St. Louis Intl. Airport (STL) at approximately 9:05AM UTC-6. The total travel time is 2h 45m.
How long does it take to fly from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
It takes about 2 hours and 41 minutes to travel the 810 mi from PHL to STL.
What airline has the least delays from PHL to STL?
Consider traveling with American Airlines if you'd like to go straight from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL) without any delays. This carrier has the strongest track record for punctuality, with an on-time performance of 82%. Want to get notified of any changes? You can keep an eye on your flight status using the Expedia App.
What is the best time to fly from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
To arrive at Lambert-St. Louis Intl. Airport (STL) on time, select a flight that leaves from Philadelphia Intl. Airport (PHL) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this hour.**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 St. Louis from Philadelphia Intl. Airport (PHL)?
If you're boarding a direct flight from Philadelphia Intl. Airport (PHL) to St. Louis, Lambert-St. Louis Intl. Airport (STL) is the only airport you can touch down at.
Is it cheaper to buy a plane ticket from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Last-minute fares from PHL to STL are generally more expensive. To secure the best prices, start searching for flights early. That being said, if you can play around with your travel dates, you may score a cheap ticket right before your journey.
Is it cheaper to book a PHL to STL flight and hotel package?
Booking a PHL to STL flight and hotel package tends to be cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip all in one place. Choose from our extensive range of hotels and then add flights, car rentals and activities to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Philadelphia Intl. Airport (PHL) to Lambert-St. Louis Intl. Airport (STL)?
If you booked your PHL to STL flight in the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the ticket type you purchased, additional charges may apply for changes beyond that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal for more information.

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*Available to One Key members.