AirHint found the following cheapest return flights from Islip (ISP) to Singapore (SIN) in September 2025 (see full year).
Return flights
| 03 Sep - 10 Sep | Cape Air |
Also check the deals for one-way flights from Islip to Singapore 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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