AirHint found the following cheapest one-way flights from St. Petersburg (PIE) to Key West (EYW) in September 2025 (see full year).
One-Way flights
| 07 Sep | Allegiant Air | direct | |
| 06 Sep | Allegiant Air | direct | |
| 04 Sep | Allegiant Air | direct | |
| 28 Sep | Allegiant Air | direct | |
| 22 Sep | Allegiant Air | direct | |
| 03 Sep | Allegiant Air | direct | |
| 29 Sep | Allegiant Air | direct |
Also check the deals for return flights from St. Petersburg to Key West in September.
The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.
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