AirHint found the following cheapest return flights from Raleigh-durham (RDU) to San Juan (SJU) in September 2025 (see full year).

Return flights

11 Sep - 14 Sep	Frontier Airlines
01 Sep - 05 Sep	Frontier Airlines
13 Sep - 20 Sep	Frontier Airlines
14 Sep - 21 Sep	Frontier Airlines
02 Sep - 07 Sep	Frontier Airlines
04 Sep - 09 Sep	Southwest Airlines

Also check the deals for one-way flights from Raleigh-durham 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 Raleigh-durham to San Juan in September from $168

Return flights