Cheapest return flights from Islip to San Juan in October from $253

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

Return flights

01 Oct - 03 Oct Frontier Airlines
04 Oct - 06 Oct Frontier Airlines
22 Oct - 28 Oct Frontier Airlines
25 Oct - 28 Oct Frontier Airlines
31 Oct - 04 Nov Frontier Airlines
25 Oct - 30 Oct Frontier Airlines
24 Oct - 28 Oct Frontier Airlines
17 Oct - 21 Oct Frontier Airlines
08 Oct - 18 Oct Frontier Airlines
08 Oct - 14 Oct Frontier Airlines
16 Oct - 19 Oct Frontier Airlines

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

Skyscanner

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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