Cheap British Airways flights Washington (IAD) to Southampton (SOU)

Scoring cheap one-way British Airways flights from IAD to SOU on Expedia is a cinch — just filter by "Price (lowest to highest)." Or check out our budget-friendly return fares from $1,992 for your next break.**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.

Getting the best British Airways deals from IAD to SOU is typically all about timing. You can save 17% on international flights when you book 18 to 29 days before takeoff instead of four to five months ahead. Better yet, you can pocket 17% on average by buying your tickets on a Sunday compared to a Friday, which is usually the most expensive day to book.* It's smart to kick off your flight search about one month before your travel dates.*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 departure from IAD to SOU with British Airways, filter your search by "Early Morning" and "Morning." Choosing an early flight generally means you'll experience fewer 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.

With a 4-star airline rating and an excellent in-flight experience, British Airways is a popular option for many travelers heading from IAD to SOU. Also, if you're a British Airways Executive Club and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles, which can be used on future trips.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.