$121 Cheap Spirit Airlines flights Philadelphia (PHL) to St. Thomas (STT)

You can discover budget-friendly return Spirit Airlines flights from $240 from PHL to STT by sorting your results from "Price (lowest to highest)" on Expedia. Or look for deals from $121 for a one-way trip.**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.

Check for Spirit Airlines flights from PHL to STT about one month before you want to leave. The most affordable time to reserve an international flight is usually 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 ticket type or itinerary, the best day to book international airfare is usually Sunday. Friday can be the most expensive. Passengers booking 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.

To find the earliest departures from PHL to STT with Spirit Airlines, filter your results by "Early Morning" and "Morning." Booking an early flight usually means you're 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 rack up points through Free Spirit are the start of the reasons to leave from PHL to STT with Spirit Airlines. Plus, when you sign up to Expedia's free One Key™ program, you can earn OneKeyCash™* in addition to 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.