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

Return flights

22 Sep - 30 Sep	Lufthansa
23 Sep - 30 Sep	Lufthansa
24 Sep - 09 Oct	Delta
24 Sep - 02 Oct	Delta
16 Sep - 25 Sep	Delta
17 Sep - 25 Sep	Delta
15 Sep - 25 Sep	Delta
18 Sep - 30 Sep	Lufthansa
16 Sep - 07 Oct	Lufthansa
18 Sep - 23 Oct	Lufthansa
16 Sep - 30 Sep	Lufthansa
18 Sep - 23 Sep	Lufthansa
22 Sep - 29 Sep	Lufthansa
15 Sep - 30 Sep	Lufthansa
17 Sep - 01 Oct	Delta
18 Sep - 16 Oct	Delta
26 Sep - 02 Oct	Delta
17 Sep - 09 Oct	Lufthansa
29 Sep - 07 Oct	KLM
25 Sep - 02 Oct	KLM

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 599€

Return flights