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

Return flights

24 Sep - 01 Oct	Air Canada
30 Sep - 06 Oct	Air Canada
29 Sep - 07 Oct	Air Canada
29 Sep - 06 Oct	Air Canada
30 Sep - 07 Oct	Air Canada
24 Sep - 02 Oct	Air Canada
26 Sep - 12 Oct	Air Canada
26 Sep - 03 Oct	Air Canada
25 Sep - 03 Oct	Air Canada
25 Sep - 01 Oct	Air Canada
25 Sep - 29 Sep	United
25 Sep - 30 Sep	United
25 Sep - 28 Sep	United
27 Sep - 30 Sep	United
26 Sep - 30 Sep	United
24 Sep - 30 Sep	Finnair
24 Sep - 28 Sep	Air Canada
22 Sep - 24 Sep	KLM
23 Sep - 30 Sep	Avianca
21 Sep - 26 Sep	Avianca

Also check the deals for one-way flights from London to Cancun 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 London to Cancun in September from $626

Return flights