$99 Cheap United flights Boise (BOI) to Phoenix (PHX)

Use the "Price (lowest to highest)" filter on Expedia to search for cheap United Airlines return flights from $197 from BOI to PHX. Affordable one-way tickets from $99 are available as well.**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 United Airlines fares from Boise Airport (BOI) to Sky Harbor Intl. Airport (PHX), start searching one to three months before your planned departure. Reserving 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 the cost. Sunday is typically 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.

Sort your results by "Early Morning" and "Morning" to browse the earliest departures from BOI to PHX. Heading off 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.

With a rewarding loyalty program, United Airlines is a favorite of many travelers departing from BOI to PHX. Plus, as a United Mileage Plus and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.