Cheapest return flights from St. Louis to San Juan in September from 231€

AirHint found the following cheapest return flights from St. Louis (STL) to San Juan (SJU) in September 2025 (see full year).

Return flights

26 Sep - 28 Sep Frontier Airlines
29 Sep - 01 Oct Frontier Airlines
20 Sep - 27 Sep Frontier Airlines
18 Sep - 21 Sep Frontier Airlines
20 Sep - 21 Sep Frontier Airlines
17 Sep - 19 Sep Southern Airways Express
19 Sep - 21 Sep Frontier Airlines
20 Sep - 20 Sep Delta

Also check the deals for one-way flights from St. Louis to San Juan in September.

Skyscanner

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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