$298 Cheap American Airlines flights St. Louis (STL) to Castries (SLU)

Landing cheap one-way American Airlines flights from STL to SLU from $298 on Expedia is a breeze --- just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly return fares from $575 for your next exciting getaway.**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.

Search for American Airlines flights from STL to SLU about one month before you want to leave. The cheapest time to reserve an international flight is generally 18 to 29 days ahead of your travel date when you can save 17% versus booking four to five months in advance. No matter your itinerary or fare class, the best day of the week to book international airfare is usually Sunday. Friday is often the most expensive. Travelers who book on a Sunday can save 17% on average 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.

Browse American Airlines's earliest flights from STL to SLU 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.