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

Return flights

23 Sep - 26 Sep	jetBlue	direct
09 Sep - 12 Sep	jetBlue	direct
07 Sep - 11 Sep	jetBlue	direct
25 Sep - 02 Oct	jetBlue	direct
08 Sep - 16 Sep	jetBlue	direct
17 Sep - 21 Sep	jetBlue	direct
02 Sep - 11 Sep	jetBlue	direct
02 Sep - 06 Sep	jetBlue	direct
08 Sep - 13 Sep	jetBlue	direct
28 Sep - 05 Oct	jetBlue	direct
21 Sep - 29 Sep	American Airlines
17 Sep - 22 Sep	Southwest Airlines

Also check the deals for one-way flights from Washington 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 Washington to San Juan in September from $259

Return flights