$129 Cheap Southwest Airlines flights Kansas City (MCI) to Washington (IAD)

Finding cheap one-way Southwest Airlines flights from MCI to IAD from $129 on Expedia is a breeze — just filter by "Price (lowest to highest)." Alternatively, check out our affordable round-trip fares from $220 for your next exciting vacation.**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.

Begin your search one to three months before your departure to score cheaper fares on Southwest Airlines flights from Kansas City Intl. Airport (MCI) to Washington Dulles Intl. Airport (IAD). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also cut costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get your timing right, and you can enjoy significant savings on domestic flights.*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 "Morning" and "Early Morning" to see the earliest departures from MCI to IAD. Heading 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.