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

Return flights

30 Sep - 30 Oct	United
30 Sep - 03 Oct	United
27 Sep - 04 Oct	United
30 Sep - 28 Oct	United
20 Sep - 27 Sep	United
30 Sep - 07 Oct	United
24 Sep - 01 Oct	United
23 Sep - 30 Sep	United
19 Sep - 27 Sep	United
29 Sep - 07 Oct	WestJet
26 Sep - 03 Oct	United
30 Sep - 10 Oct	Porter Airlines (Canada) Ltd
28 Sep - 08 Oct	Porter Airlines (Canada) Ltd
20 Sep - 25 Sep	Air Transat
20 Sep - 26 Sep	United
22 Sep - 29 Sep	United
19 Sep - 25 Sep	Porter Airlines (Canada) Ltd
19 Sep - 29 Sep	Air Canada
21 Sep - 24 Sep	WestJet
19 Sep - 26 Sep	Porter Airlines (Canada) Ltd

Also check the deals for one-way flights from Montreal to San Juan 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 San Juan in September from $263

Return flights