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

Return flights

08 Sep - 13 Oct	Ryanair
23 Sep - 07 Oct	Ryanair
25 Sep - 17 Oct	Ryanair
08 Sep - 30 Sep	Ryanair
30 Sep - 15 Oct	Ryanair
02 Sep - 29 Sep	Ryanair
09 Sep - 24 Sep	Ryanair
08 Sep - 29 Sep	Ryanair
11 Sep - 02 Oct	Ryanair
10 Sep - 02 Oct	Ryanair
14 Sep - 14 Oct	Ryanair
01 Sep - 30 Sep	Ryanair
02 Sep - 28 Sep	Ryanair
17 Sep - 30 Sep	Ryanair
08 Sep - 26 Sep	Ryanair
03 Sep - 30 Sep	Ryanair
17 Sep - 29 Sep	Ryanair
10 Sep - 03 Oct	Ryanair
27 Sep - 02 Oct	Ryanair
15 Sep - 31 Oct	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 848€

Return flights