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

Return flights

16 Sep - 23 Sep	United
07 Sep - 12 Sep	United
02 Sep - 11 Sep	United
06 Sep - 13 Sep	United
17 Sep - 24 Sep	United
23 Sep - 30 Sep	United
08 Sep - 13 Sep	United
19 Sep - 26 Sep	United
24 Sep - 01 Oct	United
27 Sep - 04 Oct	United
08 Sep - 11 Oct	United
30 Sep - 11 Oct	United
06 Sep - 20 Sep	United
24 Sep - 02 Oct	United
25 Sep - 02 Oct	United
21 Sep - 28 Sep	Porter Airlines (Canada) Ltd
29 Sep - 06 Oct	United

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