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

Return flights

10 Dec - 17 Dec	United
14 Dec - 22 Dec	Air Canada
09 Dec - 16 Dec	Delta
02 Dec - 09 Dec	United
06 Dec - 13 Dec	United
04 Dec - 11 Dec	United
08 Dec - 15 Dec	United
14 Dec - 21 Dec	Air Canada	direct
11 Dec - 18 Dec	United
12 Dec - 21 Dec	Air Transat
28 Dec - 05 Jan	WestJet
29 Dec - 05 Jan	WestJet
26 Dec - 02 Jan	WestJet
27 Dec - 03 Jan	WestJet

Also check the deals for one-way flights from Montreal to San Juan in December.

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 December from $336

Return flights