$401 Cheap United flights Seattle (SEA) to Billund (BLL)

Scoring cheap one-way United Airlines flights from SEA to BLL from $401 on Expedia is a cinch — just filter by "Price (lowest to highest)." Or check out our affordable return fares from $562 for your next exciting getaway.**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 SEA to BLL about one month before you want to leave. The most affordable time to book an international flight is usually 18 to 29 days ahead of your departure 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 is often the most expensive. Passengers who book 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.

To find the earliest departures from SEA to BLL with United Airlines, filter your results by "Morning" and "Early Morning." Choosing an early flight usually means cancellations are less likely.**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 BLL with United Airlines and look forward to a range of perks starting with a rewarding loyalty program. When you book through Expedia as a United Mileage Plus and One Key™ member, you may 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.