Cheapest return flights from Islip to San Juan in January from $204

AirHint found the following cheapest return flights from Islip (ISP) to San Juan (SJU) in January 2026 (see full year).

Return flights

26 Jan - 11 Feb Frontier Airlines
26 Jan - 12 Feb Frontier Airlines
30 Jan - 05 Feb Frontier Airlines
30 Jan - 07 Feb Frontier Airlines
30 Jan - 04 Feb Frontier Airlines
22 Jan - 28 Jan Frontier Airlines
22 Jan - 29 Jan Frontier Airlines
26 Jan - 31 Jan Frontier Airlines
25 Jan - 28 Jan Frontier Airlines
23 Jan - 28 Jan Frontier Airlines
25 Jan - 29 Jan Frontier Airlines
23 Jan - 29 Jan Frontier Airlines
23 Jan - 30 Jan Frontier Airlines
25 Jan - 30 Jan Frontier Airlines
26 Jan - 09 Feb Frontier Airlines
29 Jan - 05 Feb Frontier Airlines
22 Jan - 26 Jan Frontier Airlines
30 Jan - 01 Feb Frontier Airlines
25 Jan - 01 Feb Frontier Airlines
29 Jan - 02 Feb Frontier Airlines

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

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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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