$465 Cheap United flights St. Louis (STL) to Reykjavik (KEF)

Make use of the "Price (lowest to highest)" filter on Expedia to find cheap United Airlines round-trip flights from $587 from STL to KEF. Affordable one-way fares from $465 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.

To find cheap flights from STL to KEF with United Airlines, start your search about one month before your planned departure. You can save 17% when you lock in your international tickets 18 to 29 days ahead instead of booking four to five months in advance. Another good tip? Booking on Sunday offers average savings of 17% compared to Friday (the most expensive day).**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.

Find United Airlines's earliest flights from STL to KEF by checking our "Morning" and "Early Morning" filters. Not only will you arrive sooner, early departures are also 20% less likely to be canceled.**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.

Fly from STL to KEF with United Airlines and you can look forward to a range of perks including a rewarding loyalty program. When booking through Expedia as a United Mileage Plus and One Key™ member, you could also earn OneKeyCash™* to use on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.