$399 Cheap United flights San Francisco (SFO) to Shannon (SNN)

Finding cheap one-way United Airlines flights from SFO to SNN from $399 on Expedia couldn't be simpler — just filter by "Price (lowest to highest)." Or check out our budget-friendly return fares from $486 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.

To get affordable flights from SFO to SNN with United Airlines, start your search about one month before your planned departure. You can save 17% when you book your international tickets 18 to 29 days ahead instead of booking four to five months in advance. Another good tip? Booking on Sunday offers average savings of 17% compared to Friday (the most expensive day).**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.

Browse United Airlines's earliest flights from SFO to SNN by selecting 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.

With a rewarding loyalty program, United Airlines is a top choice for many passengers flying from SFO to SNN. Plus, if you're a United Mileage Plus and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.