Southwest® flights from St. Louis to Philadelphia from $139

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Low fares from St. Louis to Philadelphia

$

St. Louis (STL)to

Philadelphia (PHL)
Depart: 04/21/2026

One-way

Basic

From
$139
Seen: 22 hrs ago

St. Louis (STL)to

Philadelphia (PHL)
Depart: 04/22/2026

One-way

Basic

From
$139
Seen: 13 hrs ago

St. Louis (STL)to

Philadelphia (PHL)
Depart: 05/11/2026

One-way

Basic

From
$150
Seen: 22 hrs ago

St. Louis (STL)to

Philadelphia (PHL)
Depart: 05/09/2026

One-way

Basic

From
$150
Seen: 18 hrs ago

St. Louis (STL)to

Philadelphia (PHL)
Depart: 05/04/2026

One-way

Basic

From
$150
Seen: 16 hrs ago

St. Louis (STL)to

Philadelphia (PHL)
Depart: 05/28/2026

One-way

Basic

From
$150
Seen: 15 hrs ago

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Explore flights from St. Louis to Philadelphia

Mar 2026
From$296*
Seen: 14 hrs ago
One Way/Basic
Apr 2026
From$139*
Seen: 22 hrs ago
One Way/Basic
May 2026
From$150*
Seen: 22 hrs ago
One Way/Basic
$160
$464
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    • Range$160-$464

    *Fares displayed have been collected within the last 24 hours and may no longer be available at time of booking. Additional fees and charges for optional products and services may apply. Modifying this information may result in a different fare. To find the most updated fare, please visit Southwest.com. Fares listed are Basic, which are subject to additional terms and conditions.

    Flight Details

    Departing from:
    Lambert-St Louis Int'l Airport
    Arriving at:
    Philadelphia International Airport
    Average flight time:
    2 hours 7 minutes
    Distance:
    814 miles

    Route Information

    141† Weekly flights
    • 2‡ Nonstop flights per day Monday through Friday
    • 1‡ Nonstop flight on Saturday
    • 3‡ Nonstop flights on Sunday

    † Weekly flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025. Note: route may not operate every day of the week.

    ‡ Nonstop flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025.

    Questions we hear the most

    The average flight time from St. Louis to Philadelphia is 2 hours 7 minutes.
    There are 141 weekly flights from St. Louis to Philadelphia on Southwest Airlines.
    Yes, Southwest flies nonstop from St. Louis to Philadelphia 2 times per day from Monday through Friday.
    Yes, Southwest flies nonstop from St. Louis to Philadelphia once per day on Saturdays and 3 times per day on Sundays.
    To find the lowest fares by day and time to fly St. Louis to Philadelphia with Southwest, check out our Low Fare Calendar.
    You can rent a car at Philadelphia International Airport book yours with your flight.
    Yes! Flights from St. Louis to Philadelphia—or from here or there to anywhere—can be changed with no change fees. Fare difference may apply.
    Check the status of your upcoming Southwest flight.
    Check out the Southwest Airlines® Help Center for answers about everything Southwest.

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