$334 Cheap United flights Boston (BOS) to Shannon (SNN)

Grab cheap return United Airlines flights from $367 from BOS to SNN by sorting your results from "Price (lowest to highest)" on Expedia. Or search for bargains from $334 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 United Airlines flights from BOS to SNN about one month before you want to leave. The cheapest 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 fare class or itinerary, 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 an average of 17% 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 "Early Morning" and "Morning" to see the earliest flights from BOS to SNN. 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.

Offering a rewarding loyalty program, United Airlines is a top choice for many passengers journeying from BOS to SNN. Plus, if you're a United Mileage Plus and One Key™ member booking through Expedia, you can 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.