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

Return flights

06 Sep - 10 Sep	Air Canada	direct
04 Sep - 08 Sep	Air Canada
02 Sep - 10 Sep	Air Canada
04 Sep - 11 Sep	Air Canada
03 Sep - 10 Sep	Air Canada
05 Sep - 12 Sep	Air Canada
02 Sep - 09 Sep	Air Canada
08 Sep - 15 Sep	Air Canada
16 Sep - 23 Sep	Air Canada
06 Sep - 13 Sep	Air Canada
28 Sep - 05 Oct	Air Canada
25 Sep - 02 Oct	Air Canada
29 Sep - 06 Oct	Air Canada
24 Sep - 01 Oct	Air Canada
30 Sep - 07 Oct	Air France
27 Sep - 04 Oct	Air Canada
26 Sep - 03 Oct	Porter Airlines (Canada) Ltd
27 Sep - 01 Oct	Porter Airlines (Canada) Ltd
27 Sep - 01 Oct	Air Canada	direct

Also check the deals for one-way flights from Montreal 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 Montreal to Keflavik in September from $568

Return flights