$139 Cheap Delta flights Phoenix (PHX) to St. Louis (STL)

Landing cheap one-way Delta Air Lines flights from PHX to STL from $139 on Expedia is a cinch — just filter by “Price (lowest to highest).” Alternatively, check out our affordable return fares from $201 for your next getaway.**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.

Delta Air Lines flights to St. Louis tend to be more affordable in the off-peak months of January and February. Whether you’re searching for a return or one-way ticket, you could score a better deal then.

Look for cheap Delta Air Lines flights from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) one to three months before your departure day. Travelers who book domestic flights 34 to 86 days in advance can save 25% compared to those who book just 6 to 12 days ahead. Regardless of fare class and itinerary, the best day of the week to book a domestic flight is generally Sunday and the most expensive is typically Monday. Passengers who book on a Sunday can save 6% on average compared to those who book on a Monday.**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.

Use our “Nonstop” filter when searching for direct Delta Air Lines flights from PHX to STL. It’s also a good way to compare other carriers offering the same nonstop route.

To find the earliest departures from PHX to STL with Delta Air Lines, sort your results by “Morning” and “Early Morning.” Booking an early flight generally means cancellations are less likely.**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.

Lambert-St. Louis Intl. Airport (STL) is the main St. Louis gateway for Delta Air Lines flights from Sky Harbor Intl. Airport (PHX).

Taking off from PHX to STL with Delta Air Lines comes with plenty of perks, including an excellent in-flight experience and a rewarding loyalty program. Plus, when you book through Expedia, One Key™ members can earn OneKeyCash™* to spend on select future travel purchases. That’s in addition to 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.

You can usually cancel or change your flight, although additional charges may apply if you booked more than 24 hours ago. Need to keep your options open? Apply the “Changes included” and “No cancel fee” filters to find flights that won’t charge extra if you have to alter your plans. To make changes, go to “Trips,” select your flight and click on “Manage Booking” for further information.