$109 Cheap United flights Seattle (SEA) to Phoenix (PHX)

You can discover cheap return United Airlines flights from $152 from SEA to PHX by filtering your results from "Price (lowest to highest)" on Expedia. Or search for bargains from $109 for a one-way trip.**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.

Search for affordable United Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Sky Harbor Intl. Airport (PHX) one to three months ahead of your departure. 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 type and journey, the ideal day to book a domestic flight is usually Sunday and the most expensive day 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.

Find United Airlines's earliest flights from SEA to PHX by using our "Early Morning" and "Morning" filters. Not only will you arrive sooner, early departures are also 20% less likely to be 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.

Journey from SEA to PHX with United Airlines and you'll enjoy a range of benefits starting with a rewarding loyalty program. When you book through Expedia as a United Mileage Plus and One Key™ member, you can also earn OneKeyCash™* to use on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.