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

Return flights

26 Sep - 29 Sep	Avianca
22 Sep - 05 Oct	Avianca
24 Sep - 08 Oct	Avianca
26 Sep - 03 Oct	Avianca
22 Sep - 10 Oct	Avianca
22 Sep - 01 Oct	Avianca
22 Sep - 02 Oct	Avianca
24 Sep - 28 Sep	Avianca
22 Sep - 03 Oct	Avianca
24 Sep - 01 Oct	Avianca
24 Sep - 03 Oct	Avianca
22 Sep - 29 Sep	Avianca
18 Sep - 27 Oct	Ryanair
25 Sep - 29 Sep	easyJet
23 Sep - 28 Sep	Avianca
21 Sep - 29 Sep	Avianca
23 Sep - 27 Sep	Ryanair
20 Sep - 23 Sep	Ryanair
23 Sep - 25 Sep	Ryanair
18 Sep - 26 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 $1076

Return flights