$390 Cheap United flights Washington (IAD) to Reykjavik (KEF)

Make use of the "Price (lowest to highest)" filter on Expedia to find cheap United Airlines round-trip flights from $480 from IAD to KEF. Affordable one-way fares from $390 are also on offer.**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.

Scoring the best United Airlines deals from IAD to KEF 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. To top it off, 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 departure date.*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 browse the earliest departures from IAD to KEF. Leaving 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 favorite of many passengers flying from IAD to KEF. Plus, as a United Mileage Plus and One Key™ member booking through Expedia, you can earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.