$538 Cheap KLM flights St. Louis (STL) to Belgrade (BEG)

Landing cheap one-way KLM flights from STL to BEG from $538 on Expedia couldn't be simpler --- just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly return fares from $785 for your next adventure.**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 affordable flights from STL to BEG with KLM, start searching 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. Want another 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.

Search KLM's earliest flights from STL to BEG by selecting 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.

With a 4-star airline rating, KLM is a favorite of many travelers departing from STL to BEG. Plus, as a KLM Flying Blue and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.