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

Finding cheap one-way Delta Air Lines flights from STL to PHX from $139 on Expedia is simple --- just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly return fares from $222 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.

Begin your search one to three months ahead of your departure date to get cheaper fares on Delta Air Lines flights from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also reduce costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get your timing right, and you can enjoy significant savings on domestic trips.*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.

Find Delta Air Lines's earliest flights from STL to PHX by selecting the "Morning" and "Early Morning" filters. Not only will you get to your destination sooner, early departures also have a 20% less chance of being canceled.**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.

Traveling from STL to PHX with Delta Air Lines means enjoying a variety of perks, including an excellent in-flight experience and a rewarding loyalty program. Plus, when you book through Expedia, One Key™ members can collect OneKeyCash™* to redeem 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.