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

Return flights

19 Sep - 28 Sep	Avianca
19 Sep - 27 Sep	Avianca
01 Sep - 05 Sep	Avianca	direct
13 Sep - 17 Sep	Copa
15 Sep - 19 Sep	Copa
06 Sep - 13 Sep	Copa
04 Sep - 12 Sep	Copa
05 Sep - 11 Sep	Avianca
05 Sep - 13 Sep	Avianca
15 Sep - 19 Sep	Avianca	direct
19 Sep - 10 Oct	Spirit Airlines

Also check the deals for one-way flights from San Jose 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 San Jose to San Juan in September from 180€

Return flights