$398 Cheap United flights San Francisco (SFO) to Lisbon (LIS)

You'll find affordable round-trip United Airlines flights from $482 from SFO to LIS by filtering your results from "Price (lowest to highest)" on Expedia. Or search for bargains from $398 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.

Check for United Airlines flights from SFO to LIS about one month before you want to go. The most affordable time to reserve 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. Regardless of ticket type or itinerary, the best day to book international airfare is usually Sunday. Friday is often the most expensive. Travelers 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.

Filter your results by "Morning" and "Early Morning" to see the earliest flights from SFO to LIS. Setting off early means flight 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.

A rewarding loyalty program and the chance to rack up points through United Mileage Plus are the start of the reasons to fly from SFO to LIS with United Airlines. Plus, when you join Expedia's free One Key™ program, you can receive OneKeyCash™* on top of United Airlines's loyalty program earnings. It's yours to spend on your next adventure.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.