$456 Cheap Aer Lingus flights Washington (IAD) to Southampton (SOU)

You'll discover cheap round-trip Aer Lingus flights from $671 from IAD to SOU by organizing your results from "Price (lowest to highest)" on Expedia. Or search for options from $456 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 Aer Lingus flights from IAD to SOU 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 itinerary or fare class, the best day to book international airfare is usually Sunday. Friday can be the most expensive. Passengers booking 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 departures from IAD to SOU. Jetting off early means you're less likely to experience cancellations.**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.

Flying from IAD to SOU with Aer Lingus means enjoying a host of perks, including a rewarding loyalty program and a 4-star airline rating. Plus, when you book through Expedia, One Key™ members can collect OneKeyCash™* to use on select future travel purchases. That's in addition to the Aer Lingus AerClub points you can earn with Aer Lingus.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.