AirHint found the following cheapest return flights from Kansas City (MCI) to San Juan (SJU) in September 2025 (see full year).

Return flights

20 Sep - 27 Sep	Southwest Airlines
19 Sep - 23 Sep	Southwest Airlines
06 Sep - 12 Sep	Spirit Airlines
20 Sep - 04 Oct	Spirit Airlines
20 Sep - 08 Oct	Spirit Airlines
02 Sep - 05 Sep	Spirit Airlines
02 Sep - 12 Sep	Spirit Airlines
24 Sep - 28 Sep	Southwest Airlines
05 Sep - 12 Sep	Spirit Airlines
02 Sep - 10 Sep	Spirit Airlines
03 Sep - 10 Sep	Spirit Airlines
04 Sep - 05 Sep	Spirit Airlines

Also check the deals for one-way flights from Kansas City to San Juan 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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Cheapest return flights from Kansas City to San Juan in September from 184€

Return flights