$109 Cheap Delta flights St. Louis (STL) to Philadelphia (PHL)

View $109 flight on Mon, Aug 18, 2025Opens in a new window

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$109 Cheap Delta flights St. Louis (STL) to Philadelphia (PHL)

Prices were available within the past 7 days and start at $109 for one-way flights and $173 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Thu, Sep 11 - Thu, Sep 18
STL
St. Louis
PHL
Philadelphia
$173 Roundtrip, found 4 hours ago
$173
Roundtrip
found 4 hours ago
Select Delta flight, departing Thu, Sep 11 from St. Louis to Philadelphia, returning Thu, Sep 18, priced at $173 found 4 hours ago
Delta
Wed, Sep 3 - Thu, Sep 4
STL
St. Louis
PHL
Philadelphia
$217 Roundtrip, found 3 hours ago
$217
Roundtrip
found 3 hours ago
Select Delta flight, departing Wed, Sep 3 from St. Louis to Philadelphia, returning Thu, Sep 4, priced at $217 found 3 hours ago
Flights from St. Louis (STL) to Philadelphia (PHL)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Philadelphia Intl.
Airlines serving
American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Popular airline
American Airlines
Distance
811 mi
Average flight time
3 hours 14 mins

Frequently asked questions

How much is a Delta Air Lines flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Set the "Price (lowest to highest)" filter on Expedia to look for cheap Delta Air Lines return flights from $173 from STL to PHL. Affordable one-way fares from $109 are available as well.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from STL to PHL with Delta Air Lines?
January is one of the most affordable months to jet away to Philadelphia with Delta Air Lines. You could also find great deals on one-way and round-trip fares in February.
What is the cheapest time to book flights from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL) with Delta Air Lines?
To find cheap Delta Air Lines fares from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL), start searching one to three months before your intended departure. Reserving domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also impact what you pay. Sunday is typically the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your journey on a Sunday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does Delta Air Lines fly nonstop from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
To find out if there's a direct journey from STL to PHL with Delta Air Lines or other carriers, check the "Nonstop" filter when looking for flights.
What is the earliest Delta Air Lines flight from STL to PHL?
To find the earliest departure from STL to PHL with Delta Air Lines, filter your search by "Early Morning" and "Morning." Booking an early flight generally means you'll experience fewer cancellations.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does Delta Air Lines fly into in Philadelphia?
Jump on a Delta Air Lines flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia, and you'll probably land at Philadelphia Intl. Airport (PHL). This is the airline's main hub in this city.
Why fly with Delta Air Lines from STL to PHL?
Jetting off from STL to PHL with Delta Air Lines comes with a host of benefits, including an excellent in-flight experience and a rewarding loyalty program. Plus, when you book through Expedia, One Key™ members can collect OneKeyCash™* to use on select future travel purchases. That's on top of the Delta SkyMiles points you can earn with Delta Air Lines.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
Can I change or cancel my Delta Air Lines flight from Lambert-St. Louis Intl. Airport (STL) to Philadelphia Intl. Airport (PHL)?
Changes are generally free within 24 hours of making a booking, but your airline may add a charge after that time. For more information about altering your flights, check out your "Trips," select your flight and click on "Manage Booking." If you'd like the flexibility to adjust your plans without extra charges, tick the "Changes included" and "No cancel fee" filters when organizing your next break.

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*Available to One Key members.