AirHint found the following cheapest one-way flights from St. Louis (STL) to San Juan (SJU) in December 2025 (see full year).
One-Way flights
| 13 Dec | Frontier Airlines | ||
| 16 Dec | American Airlines | ||
| 28 Dec | Frontier Airlines | ||
| 13 Dec | Southwest Airlines | direct |
Also check the deals for return flights from St. Louis to San Juan in December.
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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