$1,390 Cheap United flights Guam (GUM) to Seattle (SEA)

Finding cheap one-way United Airlines flights from GUM to SEA from $1,390 on Expedia is a breeze — just filter by "Price (lowest to highest)." Alternatively, check out our affordable round-trip fares from $1,378 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.

Look for United Airlines flights from GUM to SEA about one month before you want to go. The cheapest time to book an international flight is generally 18 to 29 days ahead of your travel date when you can save 17% versus booking four to five months in advance. No matter your itinerary or ticket type, the best day of the week to book international airfare is usually Sunday. Friday can be the most expensive. Travelers booking on a Sunday can save 17% on average compared to those who book on a Friday.**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 GUM to SEA by checking the "Morning" and "Early Morning" filters. Not only will you get to your destination 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.

With a rewarding loyalty program, United Airlines is a favorite of many passengers journeying from GUM to SEA. Plus, as a United Mileage Plus and One Key™ member booking through Expedia, you can 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.