$150 Cheap Spirit Airlines flights St. Louis (STL) to St. Thomas (STT)

Apply the "Price (lowest to highest)" filter on Expedia to find cheap Spirit Airlines return flights from $303 from STL to STT. Affordable one-way fares from $150 are available too.**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 Spirit Airlines flights from STL to STT 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 departure date when you can save 17% versus booking four to five months in advance. No matter your fare class or itinerary, the best day of the week to book international airfare is usually Sunday. Friday can be the most expensive. Passengers 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.

Sort your results by "Morning" and "Early Morning" to find the earliest departures from STL to STT. Heading off early means you're 20% less likely to experience cancellations.**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.

A rewarding loyalty program and the ability to collect points through Free Spirit are the start of the reasons to jet off from STL to STT with Spirit Airlines. Plus, when you sign up to our One Key™ program, you can receive OneKeyCash™* alongside any airline loyalty program earnings. It's yours to spend on future bookings.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.