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

Return flights

17 Sep - 21 Sep	Frontier Airlines
15 Sep - 21 Sep	Frontier Airlines
26 Sep - 28 Sep	Frontier Airlines
01 Sep - 05 Sep	Frontier Airlines
28 Sep - 03 Oct	Frontier Airlines
17 Sep - 25 Sep	Spirit Airlines
15 Sep - 20 Sep	United
06 Sep - 20 Sep	United
15 Sep - 29 Sep	United
22 Sep - 30 Sep	Delta
28 Sep - 04 Oct	United
25 Sep - 09 Oct	United
01 Sep - 04 Sep	Spirit Airlines
26 Sep - 10 Oct	United
26 Sep - 01 Oct	United
28 Sep - 05 Oct	Frontier Airlines
17 Sep - 05 Oct	Spirit Airlines
17 Sep - 06 Oct	Spirit Airlines
17 Sep - 04 Oct	Spirit Airlines
25 Sep - 05 Oct	Spirit Airlines

Also check the deals for one-way flights from New York 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 New York to San Juan in September from 109€

Return flights