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

Return flights

29 Sep - 08 Oct	WestJet
23 Sep - 30 Sep	WestJet
13 Sep - 16 Sep	WestJet
06 Sep - 16 Sep	WestJet
30 Sep - 25 Oct	Air Canada
07 Sep - 11 Sep	WestJet
21 Sep - 24 Sep	WestJet
15 Sep - 24 Sep	WestJet
16 Sep - 01 Oct	WestJet
16 Sep - 30 Sep	WestJet
23 Sep - 07 Oct	WestJet	direct
21 Sep - 04 Oct	WestJet
17 Sep - 30 Sep	WestJet
06 Sep - 28 Sep	WestJet
17 Sep - 07 Oct	WestJet
14 Sep - 07 Oct	WestJet
16 Sep - 08 Oct	WestJet
23 Sep - 06 Oct	Delta
16 Sep - 18 Sep	WestJet
16 Sep - 07 Oct	WestJet

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 $559

Return flights