Cheap Frontier Airlines flights Colorado Springs (COS) to Phoenix (PHX)

Landing cheap one-way Frontier Airlines flights from COS to PHX on Expedia couldn't be simpler — just filter by "Price (lowest to highest)." Or check out our budget-friendly return fares for your next adventure.**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.

To find cheap Frontier Airlines fares from Colorado Springs Airport (COS) to Sky Harbor Intl. Airport (PHX), start searching one to three months before your intended departure. Securing domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also influence how much you pay. Sunday is generally the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your journey on a Sunday.**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.

Filter your results by "Early Morning" and "Morning" to find the earliest flights from COS to PHX. Leaving early means you're less likely to experience 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.

Offering a rewarding loyalty program, Frontier Airlines is a top pick for many passengers heading from COS to PHX. Plus, if you're a Frontier Miles and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.