A city skyline with a prominent arch bridge at sunset.

$115 Cheap Flights from Philadelphia (PHL) to St. Louis (STL)

View $115 flight on Mon, Sep 28, 2026Opens in a new window

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

  • Be in the know

    Get alerts if flight prices drop or rise*

  • Book smarter

    Save up to 30% on select hotels after you book a flight*

  • Earn twice

    Earn your airline miles on top of our OneKeyCash
    Learn about One Key

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

Prices were available within the past 7 days and start at $115 for one-way flights and $230 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Mon, Oct 12 - Wed, Nov 18
PHL
Philadelphia
STL
St. Louis
$230 Roundtrip, found 1 day ago
$230
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Mon, Oct 12 from Philadelphia to St. Louis, returning Wed, Nov 18, priced at $230 found 1 day ago
Frontier Airlines
Mon, Oct 12 - Wed, Nov 18
PHL
Philadelphia
STL
St. Louis
$245 Roundtrip, found 1 day ago
$245
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Mon, Oct 12 from Philadelphia to St. Louis, returning Wed, Nov 18, priced at $245 found 1 day ago
Frontier Airlines
Sat, Aug 29 - Mon, Aug 31
PHL
Philadelphia
STL
St. Louis
$255 Roundtrip, found 5 days ago
$255
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Sat, Aug 29 from Philadelphia to St. Louis, returning Mon, Aug 31, priced at $255 found 5 days ago
Frontier Airlines
Thu, Nov 12 - Sat, Nov 14
PHL
Philadelphia
STL
St. Louis
$258 Roundtrip, just found
$258
Roundtrip
just found
Select Frontier Airlines flight, departing Thu, Nov 12 from Philadelphia to St. Louis, returning Sat, Nov 14, priced at $258 just found
Frontier Airlines
Fri, Sep 25 - Mon, Sep 28
PHL
Philadelphia
STL
St. Louis
$260 Roundtrip, just found
$260
Roundtrip
just found
Select Frontier Airlines flight, departing Fri, Sep 25 from Philadelphia to St. Louis, returning Mon, Sep 28, priced at $260 just found
Frontier Airlines
Fri, Sep 4 - Mon, Sep 7
PHL
Philadelphia
STL
St. Louis
$262 Roundtrip, just found
$262
Roundtrip
just found
Select Frontier Airlines flight, departing Fri, Sep 4 from Philadelphia to St. Louis, returning Mon, Sep 7, priced at $262 just found
Southwest Airlines
Mon, Oct 5 - Thu, Oct 8
PHL
Philadelphia
STL
St. Louis
$265 Roundtrip, found 17 hours ago
$265
Roundtrip
found 17 hours ago
Select Southwest Airlines flight, departing Mon, Oct 5 from Philadelphia to St. Louis, returning Thu, Oct 8, priced at $265 found 17 hours ago
American Airlines
Sat, Sep 5 - Sun, Sep 6
PHL
Philadelphia
STL
St. Louis
$277 Roundtrip, found 13 hours ago
$277
Roundtrip
found 13 hours ago
Select American Airlines flight, departing Sat, Sep 5 from Philadelphia to St. Louis, returning Sun, Sep 6, priced at $277 found 13 hours ago
Delta
Sat, Sep 5 - Sun, Sep 6
PHL
Philadelphia
STL
St. Louis
$297 Roundtrip, found 13 hours ago
$297
Roundtrip
found 13 hours ago
Select Delta flight, departing Sat, Sep 5 from Philadelphia to St. Louis, returning Sun, Sep 6, priced at $297 found 13 hours ago
United
Sat, Sep 5 - Sun, Sep 6
PHL
Philadelphia
STL
St. Louis
$297 Roundtrip, found 13 hours ago
$297
Roundtrip
found 13 hours ago
Select United flight, departing Sat, Sep 5 from Philadelphia to St. Louis, returning Sun, Sep 6, priced at $297 found 13 hours ago

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 $300
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $300

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

October is typically the cheapest month to fly

From $198 - $291 per traveler.

What you need to know for your flight from Philadelphia Intl. to Lambert-St. Louis Intl.

Philadelphia (PHL) to St. Louis (STL) at a glance

Travel from Philadelphia (PHL) to St. Louis (STL) with a range of airlines offering convenient domestic routes. Whether you're seeking affordable options or full-service flights, you can compare choices to discover the itinerary that aligns with your budget and travel plans. As you prepare to explore the iconic attractions and neighborhoods of St. Louis, be sure to check the essential details for flights from Philadelphia International Airport to Lambert-St. Louis International Airport.

  • Fastest flight duration: around 2h 30m non-stop
  • Route distance: roughly 800 miles (1,290 km)
  • Flights per week: around 20+ flights with multiple daily departures on average
  • Typical fares (one-way): economy tickets often range from $110–$455, depending on seasonality and how far ahead you book

Flights from Philadelphia International Airport (PHL) to Lambert-St. Louis International Airport (STL)

Based on the latest traveler bookings, here are the top airlines preferred for flights from Philadelphia to St. Louis, focusing on both non-stop and one-stop options. Common layovers include Orlando International Airport (MCO) with an average layover of about 2 hours and 30 minutes, Hartsfield-Jackson Atlanta International Airport (ATL) at approximately 1 hour and 45 minutes, and Detroit Metropolitan Wayne County Airport (DTW) with a shorter layover of around 55 minutes. These choices allow you to balance price, total travel time, and cabin class while crafting the ideal itinerary.

  • American Airlines: This comprehensive carrier provides both non-stop and one-stop flights, with one-way fares generally falling between $115 and $455. It represents about 52% of departures for this route, featuring a standard non-stop flight duration of 2 hours and 30 minutes.
  • Southwest Airlines: Known for its budget-friendly options, this airline also offers non-stop and one-stop services, with one-way fares usually ranging from $110 to $455. It accounts for around 34% of route departures, with a typical non-stop travel time of 2 hours and 30 minutes.
  • Frontier Airlines: As a low-cost option, Frontier provides one-stop services, with one-way fares typically spanning from $110 to $215. This airline handles about 9% of departures on this route, with an in-flight duration of 4 hours and an overall journey time of approximately 5 hours and 45 minutes, including layover time.
  • Delta: Offering one-stop services, Delta is a full-service airline with one-way fares generally between $150 and $500. It constitutes around 5% of departures on this route and has an in-flight time of 4 hours, with total travel time close to 5 hours and 45 minutes, factoring in a layover.
  • United: A full-service airline providing one-stop service, United's one-way fares typically range from $170 to $785. This carrier makes up approximately 1% of departures on this route, featuring an in-flight duration of 4 hours and a total journey time of near 5 hours and 45 minutes, including layover time.

Travelers flying from Philadelphia to St. Louis have the option to upgrade their experience. American Airlines features first-class service, while Delta provides both first class and premium economy cabins for added comfort.

Best time to fly from Philadelphia (PHL) to St. Louis (STL)

The most popular months for travelers flying from Philadelphia to St. Louis are March, April, and August, when peak temperatures in St. Louis reach up to 77°F in August. If you prefer quieter travel, consider September, the least busy and relatively cheaper time to visit with fewer crowds and temperatures around 70.9°F. For better deals, August usually offers the lowest average one-way fare around $206. Flight availability peaks in November, with approximately 28 flights per week, making it easier to find convenient departure times. January and February have the fewest flights, with approximately 16 flights per week.

  • Cheapest time to fly: August usually offers good deals with average one-way fare around $206, roughly 17% cheaper than the yearly average.
  • More budget-friendly months to fly: September and October typically offer average one-way fares roughly ranging from $215 to $226.
  • Most flight options: November has the highest number of flights from Philadelphia to St. Louis, with approximately 28 flights per week, giving you more flexibility in scheduling your trip.
calendar iconMonthtemperature iconTemperaturecrowd level iconDemandflights iconWeekly Flightsprice iconAverage one-way Fare
January31.6°F (-0.2°C)Average16$256
February34.9°F (1.6°C)Low16$274
March46.4°F (8.0°C)High19$290
April56.1°F (13.4°C)High24$243
May66.6°F (19.2°C)Average24$253
June76.1°F (24.5°C)Average25$274
July78.6°F (25.9°C)Average24$261
August77.0°F (25.0°C)High24$206
September70.9°F (21.6°C)Low22$215
October58.6°F (14.8°C)Average25$226
November46.2°F (7.9°C)Average28$260
December37.8°F (3.2°C)Low21$251

*Average one-way fare is based on Expedia flight booking data from January 2025 to April 2026 for the specified route and travel class and may change depending on availability, dates, and demand.

Alternative route from Philadelphia (PHL) to St. Louis (STL)

  • Trenton to St. Louis (TTN-STL): Mercer Airport (TTN) is located approximately 36 miles from Philadelphia International Airport (PHL). One-way economy ticket prices on this route generally vary from $80 to $215, influenced by the time of year and when you book. Travelers can expect primarily one-stop flights, with common layover points being Orlando International Airport (MCO) and Hartsfield-Jackson Atlanta International Airport (ATL). Popular airlines operating this route include Frontier Airlines (a budget carrier) and American Airlines.

How to find the best prices for flights from Philadelphia (PHL) to St. Louis (STL)

Getting some of the best deals on flights from Philadelphia to St. Louis is all about timing and flexibility. Here are some key tips to help you save:

  1. Best times to book and fly: cheaper fares are usually available when booking at least 2 months in advance, although most travelers tend to book 2-8 weeks ahead. Afternoon departures from 12 PM to 6 PM often offer lower prices, while morning flights from 5 AM to 12 PM are the most popular. Additionally, flying on Saturday generally provides cheaper options, although Thursday is the busiest travel day.
  2. Set up price alerts: stay updated on price changes by using Expedia's Price Tracker. Receive alerts when fares drop for your selected route.
  3. Bundle and save: bundle your flight and hotel to save on Expedia, or unlock a hotel deal after booking your flight.*
  4. Compare flight options: use Expedia's search tool to compare airlines, routes, direct vs. non-direct flights, and flight times. You can also sort by price to find the most affordable options.
  5. Stay flexible with dates: being open to different travel days can sometimes help you find better prices on flights and hotels.
  6. Think about luggage: nowadays, it's important to check the airline's baggage policies to find the best value. That may be paying for an additional carry-on bag or booking a ticket with checked luggage included. Either way, double-check your allowance before confirming your booking to avoid excess baggage fees at the airport.

*Members only. Savings vary and are not available on all bundles. Select hotels.

Arriving at Lambert-St. Louis International Airport from Philadelphia International Airport

St. Louis welcomes travelers from Philadelphia with a range of transport options based on price, convenience, and proximity. Here's how to reach St. Louis efficiently:

  • Hotel transfer: Transfers offer a convenient way to reach your hotel in St. Louis, with private rides that can be arranged in advance.
  • Car rental: Renting a car from Lambert-St. Louis International Airport is a great option if you plan to explore and sightsee beyond the city. Browse cheap car rentals at Lambert-St. Louis International Airport on Expedia.
  • Taxi/ride-hailing: Taxis and ride-hailing services may be available from designated pickup areas outside the terminal, check locally on arrival.
  • Public transportation: From Lambert-St. Louis International Airport, Lambert Main Terminal Station (a metro station) is conveniently located just 0.1 miles away on foot, providing easy access for travelers.

Frequently asked questions

How much does a flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) cost?
You can find cheap one-way flights from $115 and cheap return flights from $230 Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) with Expedia. One-way flights typically cost between $167 and $821, and return flights often range between $352 and $1340. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) ticket fares go up or down.*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.
What is the cheapest month to fly from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The cheapest month to fly from PHL to STL is October when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you're able to. Use the calendar view in your search to see which months have low fares on this route.
Which airlines fly direct from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
You can fly direct from PHL to STL on American Airlines, with around 22 flights per week.
What is the cheapest airline that flies from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Southwest Airlines is one of the cheapest airlines offering nonstop flights from Philadelphia, PA (PHL) to St. Louis, MO (STL), with round-trip tickets starting from around $203. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.*Prices based on flights available on Expedia in the last year.
How do I find cheap flights from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
To find a cheap flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best airline to fly with from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The best airline to fly with from Philadelphia, PA (PHL) to St. Louis, MO (STL) will differ from traveler to traveler. If you like to fly early, WN offers early morning flights. If price is the most important factor, WN typically offers the lowest fares. American Airlines offers the most daily flights from PHL to STL, which is great if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.
What is the best time to fly from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
How many flights per day from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
On average, there are around 5 nonstop flights per day from Philadelphia Intl. (PHL) to Lambert-St. Louis Intl. (STL). For more options, look at flights that include layovers.
What is the earliest flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The earliest flight from Philadelphia International Airport (PHL) to Lambert-St. Louis International Airport (STL) typically departs at around 5:00 AM. This flight is operated by American Airlines and Southern Airways Express. An early departure like this can help you make the most of your day in St. Louis. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What are the most popular departure times for flights from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
When flying from Philadelphia (PHL-Philadelphia Intl.) to St. Louis (STL-Lambert-St. Louis Intl.), the most popular departure times are in the early morning, from 6am to 9am. About 25% of passengers prefer this time window. Many major carriers, including American Airlines, Delta, and United Airlines, offer flights during this time. This is a great option for travelers looking to maximize their day in St. Louis.
How long does it take to fly from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Flying nonstop from PHL to STL takes around 2 hours 50 minutes, with the route covering approximately 811 miles. Flights with a layover typically take 2 hours 30 minutes longer than direct options. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
You can fly first class between PHL and STL. First class cabins are available on:

  • Delta Air Lines
  • American Airlines
  • United Airlines
  • Spirit Airlines

How much is a business class flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
A direct, return business class ticket from Philadelphia (PHL) to St. Louis (STL) typically costs between $998 - $1,453. Prices often fluctuate based on seasonality and how early you book. You may also be able to find a cheaper business class journey between Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) if you opt for a connecting flight.*Prices based on flights available on Expedia in the last year.
How do I earn miles on a Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight with Expedia?
It's easy to earn miles on a Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for St. Louis from Philadelphia Intl. (PHL)?
If you're planning to travel to St. Louis from Philadelphia Intl. (PHL), you can fly into Lambert-St. Louis Intl. (STL) Some flights may connect through major hubs like Washington Dulles Intl. (IAD), Midway Intl. (MDW), Nashville Intl. (BNA) before reaching St. Louis. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) at the last minute?
Typically, booking a last minute flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight and hotel package?
Securing a Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) St Louis Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
If you booked your Philadelphia, PA (PHL-Philadelphia Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Philadelphia Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Roundtrip price
$230
Distance
811 mi
Average flight time
1 hour 23 mins

Book with confidence

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 October. 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 $115 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.

 

Philadelphia to St. Louis Flights

*Flight schedules are subject to change.

*Available to One Key members.

 

Explore a world of travel with Expedia