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

Return flights

15 Sep - 25 Sep	Delta
16 Sep - 25 Sep	Delta
10 Sep - 24 Sep	Delta
18 Sep - 29 Sep	Delta
11 Sep - 17 Sep	Delta
18 Sep - 09 Oct	Delta
17 Sep - 01 Oct	Delta
22 Sep - 29 Sep	Delta
17 Sep - 25 Sep	Delta
10 Sep - 15 Sep	Delta
17 Sep - 24 Sep	Delta
24 Sep - 29 Sep	Delta
24 Sep - 01 Oct	Delta
26 Sep - 01 Oct	Delta
30 Sep - 10 Oct	Delta
29 Sep - 05 Oct	Delta
23 Sep - 10 Oct	Delta
24 Sep - 10 Oct	Delta
19 Sep - 07 Oct	Delta
26 Sep - 10 Oct	Delta

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 $711

Return flights