Cheap Spirit Airlines flights Philadelphia (PHL) to Denver (DEN)

Apply the "Price (lowest to highest)" filter on Expedia to find cheap Spirit Airlines round-trip flights from PHL to DEN. Affordable one-way options are also on offer.**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.

Start searching one to three months ahead of your travel date to find cheaper fares on Spirit Airlines flights from Philadelphia Intl. Airport (PHL) to Denver Intl. Airport (DEN). 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.* Nail your timing, 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.

Search Spirit Airlines's earliest flights from PHL to DEN by selecting our "Morning" and "Early Morning" filters. Not only will you arrive sooner, early departures also experience 20% 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.

Depart from PHL to DEN with Spirit Airlines and you can look forward to a host of benefits starting with a rewarding loyalty program. When you book through Expedia as a Free Spirit and One Key™ member, you can also earn OneKeyCash™* to spend on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.