Cheapest return flights from St. Louis to San Juan in September from 175€

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

Return flights

16 Sep - 24 Sep Southwest Airlines
16 Sep - 23 Sep Southwest Airlines
20 Sep - 23 Sep Southwest Airlines
17 Sep - 23 Sep Southwest Airlines
19 Sep - 23 Sep Southwest Airlines
16 Sep - 22 Sep Southwest Airlines
09 Sep - 12 Sep Southwest Airlines
04 Sep - 08 Sep Spirit Airlines
03 Sep - 08 Sep Frontier Airlines
04 Sep - 10 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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