AirHint found the following cheapest return flights from New York (LGA) to Keflavik (KEF) in September 2025 (see full year).

Return flights

29 Sep - 07 Oct	Air France
09 Sep - 16 Sep	Delta
07 Sep - 15 Sep	Air France
08 Sep - 15 Sep	Air France
28 Sep - 06 Oct	KLM
11 Sep - 14 Sep	Air Canada
08 Sep - 14 Sep	United
10 Sep - 14 Sep	United
07 Sep - 12 Sep	Air France
08 Sep - 12 Sep	Air France
10 Sep - 17 Sep	United
07 Sep - 14 Sep	Air Canada
22 Sep - 01 Oct	Spirit Airlines
25 Sep - 03 Oct	Air Canada
30 Sep - 08 Oct	Air France
23 Sep - 01 Oct	jetBlue
11 Sep - 04 Oct	Spirit Airlines
08 Sep - 16 Oct	Spirit Airlines
24 Sep - 02 Oct	Porter Airlines (Canada) Ltd
14 Sep - 04 Oct	Spirit Airlines

Also check the deals for one-way flights from New York to Keflavik 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 New York to Keflavik in September from $394

Return flights