Skyscanner home

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

Return selected
Return selected
origin
Enter the city you're flying from, or choose from the options below
Include nearby airports
    selected
    destination
    . Enter your destination, or choose from the options below
    Include nearby airports
      selected
      Travellers and cabin class, 1 Adult, Economy
      American Airlines
      Qatar Airways
      Southwest Airlines
      Iberia
      Aer Lingus
      British Airways

      Compare St Louis to Philadelphia International flight deals

      Find the cheapest month or even day of the year to fly to Philadelphia International

      Book the best Philadelphia International fare with no extra fees

      Flight deals from St Louis to Philadelphia International

      Looking for a cheap last-minute deal or the best return flight from St Louis Airport to Philadelphia International Airport? If you want to travel next month, return fares start from $247. Find the lowest prices on one-way and return tickets right here.
      Philadelphia.$123 per passenger.Departing Mon, 12 Oct, returning Wed, 14 Oct.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Mon, 12 Oct, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Wed, 14 Oct, arriving in St Louis.Price includes taxes and charges.From $123, select.
      Philadelphia.$176 per passenger.Departing Wed, 30 Sep, returning Wed, 21 Oct.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Wed, 30 Sep, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Wed, 21 Oct, arriving in St Louis.Price includes taxes and charges.From $176, select.
      Philadelphia.$194 per passenger.Departing Fri, 30 Oct, returning Fri, 13 Nov.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Fri, 30 Oct, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Fri, 13 Nov, arriving in St Louis.Price includes taxes and charges.From $194, select.
      Philadelphia.$247 per passenger.Departing Fri, 18 Sep, returning Mon, 21 Sep.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Fri, 18 Sep, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Mon, 21 Sep, arriving in St Louis.Price includes taxes and charges.From $247, select.
      Philadelphia.$301 per passenger.Departing Thu, 12 Nov, returning Mon, 16 Nov.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Thu, 12 Nov, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Mon, 16 Nov, arriving in St Louis.Price includes taxes and charges.From $301, select.
      Philadelphia.$354 per passenger.Departing Wed, 17 Feb, returning Wed, 24 Feb.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Wed, 17 Feb, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Wed, 24 Feb, arriving in St Louis.Price includes taxes and charges.From $354, select.
      Philadelphia.$357 per passenger.Departing Wed, 9 Dec, returning Sun, 13 Dec.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from St Louis on Wed, 9 Dec, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Sun, 13 Dec, arriving in St Louis.Price includes taxes and charges.From $357, select.
      Philadelphia.$382 per passenger.Departing Tue, 15 Sep, returning Wed, 16 Sep.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Tue, 15 Sep, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Wed, 16 Sep, arriving in St Louis.Price includes taxes and charges.From $382, select.
      Philadelphia.$382 per passenger.Departing Wed, 4 Nov, returning Sat, 7 Nov.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Wed, 4 Nov, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Sat, 7 Nov, arriving in St Louis.Price includes taxes and charges.From $382, select.
      Philadelphia.$382 per passenger.Departing Wed, 14 Oct, returning Sat, 17 Oct.Return flight with American Airlines.Outbound direct flight with American Airlines departs from St Louis on Wed, 14 Oct, arriving in Philadelphia International.Inbound direct flight with American Airlines departs from Philadelphia International on Sat, 17 Oct, arriving in St Louis.Price includes taxes and charges.From $382, select.
      Philadelphia.$383 per passenger.Departing Thu, 17 Dec, returning Tue, 22 Dec.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Thu, 17 Dec, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Tue, 22 Dec, arriving in St Louis.Price includes taxes and charges.From $383, select.
      Philadelphia.$427 per passenger.Departing Fri, 25 Sep, returning Fri, 2 Oct.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Fri, 25 Sep, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Fri, 2 Oct, arriving in St Louis.Price includes taxes and charges.From $427, select.
      Philadelphia.$487 per passenger.Departing Thu, 29 Oct, returning Sun, 1 Nov.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Thu, 29 Oct, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Sun, 1 Nov, arriving in St Louis.Price includes taxes and charges.From $487, select.
      Philadelphia.$507 per passenger.Departing Sat, 19 Dec, returning Sat, 16 Jan.Return flight with United.Outbound indirect flight with United, departs from St Louis on Sat, 19 Dec, arriving in Philadelphia International.Inbound indirect flight with United, departs from Philadelphia International on Sat, 16 Jan, arriving in St Louis.Price includes taxes and charges.From $507, select.
      Philadelphia.$544 per passenger.Departing Sat, 19 Dec, returning Sat, 16 Jan.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Sat, 19 Dec, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Sat, 16 Jan, arriving in St Louis.Price includes taxes and charges.From $544, select.
      Philadelphia.$571 per passenger.Departing Fri, 1 Jan, returning Fri, 8 Jan.Return flight with Southwest Airlines.Outbound direct flight with Southwest Airlines departs from St Louis on Fri, 1 Jan, arriving in Philadelphia International.Inbound direct flight with Southwest Airlines departs from Philadelphia International on Fri, 8 Jan, arriving in St Louis.Price includes taxes and charges.From $571, select.

      Find the cheapest month to fly from St Louis to Philadelphia International

      We’re always keeping an eye on fares, so you can find the best one in seconds. It looks like St Louis to Philadelphia International flights are currently cheapest in October.
      Aug
      Find prices
      Sep
      from $247
      Oct
      from $123
      Nov
      from $301
      Dec
      from $357
      Jan
      from $571
      Feb
      from $354
      Mar
      from $691
      Apr
      from $633
      May
      Find prices
      Jun
      from $633
      Jul
      Find prices

      Direct flights from St Louis to Philadelphia International

      Aer Lingus
      American Airlines
      British Airways
      Iberia
      Qatar Airways
      Southwest Airlines

      St Louis to Philadelphia International: Alternative routes

      Compare routes from St Louis to Philadelphia below. You may find an airport to fly into that's cheaper, faster, or easier than Philadelphia International.

      Philadelphia International

      11km from central Philadelphia
      ClosestCheapest
      from $123
      Search flights

      Philadelphia Trenton-Mercer

      47km from central Philadelphia
      from $307
      Search flights

      Greater Wilmington

      49km from central Philadelphia
      Search flights

      Atlantic City International

      75km from central Philadelphia
      Search flights

      Allentown

      81km from central Philadelphia
      from $409
      Search flights

      St Louis to Philadelphia: Flight information

      The things to know before you go.
      Cheapest flight found$123
      Cheapest month to flyOctober
      Average flight time2 hrs, 16 mins
      Most popular airlineAmerican Airlines
      Average flights per week130

      Finding cheap flights from St Louis to Philadelphia International: Frequently asked questions

      The best price we found for a return flight from St Louis to Philadelphia International is $123. This is an estimate based on information collected from different airlines and travel providers over the last 4 days and is subject to change and availability.
      2 hours and 16 minutes is the average flight time from St Louis to Philadelphia International.
      American Airlines, Qatar Airways and Southwest Airlines fly direct from St Louis to Philadelphia International.
      As of August 2026, there are 130 flights per week flying from St Louis to Philadelphia International.
      The cheapest month to fly from St Louis to Philadelphia International is usually October.
      After crunching the numbers on our flight calendar, we found that it's currently cheapest to fly from St Louis Airport to Philadelphia International Airport on Monday, 12 October 2026.
      Yes – the average flight time is 2 hours and 16 minutes.
      We show every price from over 1,200 airlines and travel agents, comparing them all so you don’t have to. If you know you want to fly to Philadelphia International but you’re not ready to book, set up a Price Alert. We’ll track prices for you, and let you know when they rise or fall.

      We crunched all the numbers in our flight calendar and it looks like the cheapest time to book a flight to Philadelphia is around 40 days in advance, so don’t leave your flight to the last minute.

      Currently, Frontier Airlines and Southwest Airlines offer the cheapest flight tickets to Philadelphia International.

      Travelling from St Louis Airport (STL) to Philadelphia International Airport (PHL): what you need to know

      • The average length of a direct flight from St Louis Airport to Philadelphia International Airport is 2 hours 15 minutes.

      • Philadelphia is one hour ahead of St Louis and is in the UTC-5 timezone.

      • Flights from STL to PHL start from 06:00 — the first with American Airlines. The latest departure is at 21:00 with Southwest Airlines. Overall, you can take your pick of 26 weekly St Louis Airport to Philadelphia International Airport flights.

      • Get to the airport on time so you don't miss your STL to PHL flight. Be there at least two hours ahead for international flights and an hour early for domestic departures to avoid a last-minute sprint to the gate.

      • You can expect longer lines in popular months such as July. Arriving up to four hours ahead of international flights and two hours for domestic departures will help ensure a smooth travel experience.

      • Getting to Philadelphia (and then exploring more of the United States!) is a breeze with American Airlines. This popular airline offers direct flights from St Louis Airport to Philadelphia International Airport.

      • Most passengers choose to travel with American Airlines on this route.

      • With 78.76% of its services arriving as planned, American Airlines is the most punctual carrier operating STL to PHL flights.

      • If you want to add a stop to your trip, simply deselect 'Direct flights only' when searching for your ticket from St Louis Airport to Philadelphia International Airport. Here are the most popular stopovers between STL and PHL:

        • Detroit Wayne County Airport

        • Nashville Airport

        • Chicago Midway Airport

      How to find the cheapest flights from St Louis Airport (STL) to Philadelphia International Airport (PHL)

      • At the moment, $58 is the cheapest price we've found for a one-way St Louis Airport to Philadelphia International Airport flight. The best price for a return ticket is $123. Bear in mind that fares could change due to demand when booking.

      • To score cheap tickets from STL to PHL, reserve your trip one month before your departure.

      • The cheapest month for flights from St Louis Airport to Philadelphia International Airport is June. Use the 'Whole month' tool to find the lowest prices if you have flexible dates.

      • Snapping up cheap flights from STL to PHL is a piece of cake with Price Alerts. All you need to do is create one of these automatic alerts and we'll get in touch as soon as a new deal comes up.

      • Choose your ideal departure and arrival times, number of stops and airlines with the filters. Or sort your results by 'Cheapest' to get the best deals on flights from St Louis Airport to Philadelphia International Airport.

      Handy information about St Louis Airport (STL)

      Arriving at Philadelphia International Airport (PHL)

      When to fly to Philadelphia International Airport (PHL)

      • It's time to work out your travel dates for your flight from St Louis Airport to Philadelphia International Airport. August is the busiest month to head to Philadelphia. If you prefer a quieter vibe, go in March.

      • The warmest month in Philadelphia is July, with the temperature ranging between 18ºC (64ºF) and 32ºC (90ºF). Lock in your flights from St Louis Airport to Philadelphia International Airport in this month if you like this kind of weather.

      • For cooler conditions, search for a cheap ticket from STL to PHL in January. Temperatures average between -7ºC (19ºF) and 9ºC (48ºF) then.

      Explore more of the United States

      • Philadelphia has its own special appeal, but there are so many other corners of the United States waiting to be discovered. About 129 kilometres north-east of Philadelphia, a visit to New York will keep your itinerary packed. Don't miss top attractions like Central Park, Statue of Liberty and Metropolitan Museum of Art.

      • Around 434 kilometres north-east of Philadelphia, Boston is another essential stop in the United States. Get a taste of what this destination has to offer at Museum of Fine Arts Boston, Freedom Trail and USS Constitution Museum.

      Plan smart, explore more

      Where should Australians travel this year?

      What are the cheapest days and weeks to fly?

      5 best premium economy airlines worth paying for

      How to search for multi-city flights with Skyscanner

      Prices shown on this page are estimated lowest prices only. Found in the last 12 days.