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

Return flights

03 Dec - 10 Dec	Porter Airlines (Canada) Ltd
01 Dec - 02 Dec	Air Transat
01 Dec - 06 Dec	Air Transat
01 Dec - 08 Dec	Air Transat
08 Dec - 15 Dec	TAP
10 Dec - 17 Dec	TAP
05 Dec - 12 Dec	TAP
03 Dec - 13 Dec	TAP
24 Dec - 31 Dec	TAP
02 Dec - 09 Dec	Air Transat
31 Dec - 07 Jan	TAP
27 Dec - 10 Jan	Azores Airlines
19 Dec - 05 Jan	Air Transat
25 Dec - 01 Jan	Air Transat
30 Dec - 06 Jan	Air Transat
29 Dec - 05 Jan	TAP
28 Dec - 04 Jan	TAP
19 Dec - 03 Jan	Air Transat
27 Dec - 03 Jan	Air Transat
07 Dec - 04 Jan	SWISS

Also check the deals for one-way flights from Montreal to London 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 London in December from 468€

Return flights