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

Return flights

19 Sep - 26 Sep	United
20 Sep - 27 Sep	United
19 Sep - 28 Sep	Spirit Airlines
24 Sep - 05 Oct	Spirit Airlines
19 Sep - 23 Sep	Copa
19 Sep - 21 Sep	Copa
18 Sep - 22 Sep	Copa
24 Sep - 06 Oct	Spirit Airlines
19 Sep - 22 Sep	Copa
20 Sep - 05 Oct	Spirit Airlines
20 Sep - 21 Sep	Copa
19 Sep - 20 Sep	Copa
20 Sep - 06 Oct	Spirit Airlines
20 Sep - 22 Sep	Spirit Airlines
18 Sep - 05 Oct	Spirit Airlines
18 Sep - 06 Oct	Spirit Airlines

Also check the deals for one-way flights from Cancun 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 Cancun to San Juan in September from 341€

Return flights