Cheapest return flights from Islip to San Juan in July from $518

Best time to book flights for Islip (ISP) to San Juan (SJU) flights at AirHint

AirHint found the following cheapest return flights from Islip (ISP) to San Juan (SJU) in July 2025 (see full year).

Return flights

03 Jul - 07 Jul Southwest Airlines
26 Jul - 31 Jul Frontier Airlines
03 Jul - 08 Jul Frontier Airlines
31 Jul - 07 Aug Frontier Airlines
31 Jul - 04 Aug Frontier Airlines
03 Jul - 06 Jul Frontier Airlines
24 Jul - 28 Jul Frontier Airlines
09 Jul - 16 Jul Frontier Airlines
25 Jul - 28 Jul Frontier Airlines
09 Jul - 15 Jul Frontier Airlines
10 Jul - 13 Jul Frontier Airlines
02 Jul - 08 Jul Frontier Airlines

Also check the deals for one-way flights from Islip to San Juan in July.

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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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