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

Return flights

17 Sep - 24 Sep	United
19 Sep - 26 Sep	United
23 Sep - 30 Sep	United
20 Sep - 27 Sep	United
24 Sep - 01 Oct	United
30 Sep - 07 Oct	United
06 Sep - 13 Sep	United
16 Sep - 23 Sep	United
22 Sep - 29 Sep	United
18 Sep - 25 Sep	United
28 Sep - 05 Oct	United
07 Sep - 18 Sep	Porter Airlines (Canada) Ltd
30 Sep - 05 Oct	United
02 Sep - 09 Sep	United
25 Sep - 02 Oct	Porter Airlines (Canada) Ltd
26 Sep - 03 Oct	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 240€

Return flights