$388 Cheap KLM flights Boston (BOS) to Southampton (SOU)

Make use of the "Price (lowest to highest)" filter on Expedia to look for cheap KLM return flights from $721 from BOS to SOU. Affordable one-way options from $388 are also available.**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 KLM flights from BOS to SOU 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 departure date when you can save 17% versus booking four to five months in advance. Regardless of itinerary or fare class, the best day of the week to book international airfare is usually Sunday. Friday is often the most expensive. Travelers 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.

To find the earliest departure from BOS to SOU with KLM, sort your results by "Early Morning" and "Morning." Booking an early flight usually means 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 4-star airline rating and the ability to rack up points through KLM Flying Blue are the start of the reasons to leave from BOS to SOU with KLM. Plus, when you join our One Key™ program, you can receive OneKeyCash™* on top of any airline loyalty program earnings. You can put it toward your future trips.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.