AirHint found the following cheapest return flights from Calgary (YYC) to London (LHR) in September 2025 (see full year).

Return flights

29 Sep - 21 Oct	WestJet	direct
18 Sep - 03 Oct	WestJet
20 Sep - 27 Sep	Air Canada
05 Sep - 11 Sep	WestJet
07 Sep - 14 Sep	WestJet
22 Sep - 06 Oct	Virgin Atlantic
12 Sep - 22 Sep	Air Canada
09 Sep - 17 Sep	WestJet
22 Sep - 25 Sep	WestJet
18 Sep - 26 Sep	Finnair
06 Sep - 13 Sep	Finnair
09 Sep - 16 Sep	Finnair
17 Sep - 30 Sep	Finnair
25 Sep - 01 Oct	Finnair
25 Sep - 02 Oct	Finnair
15 Sep - 07 Oct	British Airways
30 Sep - 06 Oct	Delta
30 Sep - 07 Oct	British Airways
26 Sep - 01 Oct	Air Canada
24 Sep - 06 Oct	Air Canada

Also check the deals for one-way flights from Calgary to London 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 Calgary to London in September from 535€

Return flights