AirHint found the following cheapest return flights from London (STN) to Buenos Aires (AEP) in September 2025 (see full year).

Return flights

14 Sep - 14 Oct	Ryanair
18 Sep - 25 Oct	Ryanair
17 Sep - 27 Oct	Ryanair
14 Sep - 30 Sep	Ryanair
19 Sep - 25 Oct	Ryanair
19 Sep - 12 Oct	Ryanair
02 Sep - 30 Sep	Ryanair
18 Sep - 06 Oct	Ryanair
18 Sep - 08 Oct	Ryanair
17 Sep - 16 Oct	Ryanair
19 Sep - 26 Sep	Ryanair
18 Sep - 05 Oct	Ryanair
01 Sep - 30 Sep	Ryanair
06 Sep - 06 Oct	Ryanair
23 Sep - 30 Sep	Ryanair
19 Sep - 30 Sep	Ryanair
09 Sep - 30 Sep	Ryanair
23 Sep - 29 Sep	Ryanair
12 Sep - 26 Sep	Ryanair
02 Sep - 29 Sep	Ryanair

Also check the deals for one-way flights from London to Buenos Aires 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 Buenos Aires in September from $1040

Return flights