$338 Cheap American Airlines flights Philadelphia (PHL) to Castries (SLU)

You'll discover affordable return American Airlines flights from $557 from PHL to SLU by sorting your results from "Price (lowest to highest)" on Expedia. Or look for bargains from $338 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 American Airlines flights from PHL to SLU about one month before you want to leave. The most affordable 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. Regardless of itinerary and fare class, the best day to book international airfare is usually Sunday. Friday is often 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 flights from PHL to SLU. Leaving early 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.