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

Return flights

25 Sep - 17 Oct	Ryanair
10 Sep - 23 Sep	Ryanair
15 Sep - 25 Sep	Air France
07 Sep - 21 Sep	Ryanair
11 Sep - 27 Sep	TAP
11 Sep - 24 Sep	TAP
01 Sep - 29 Sep	TAP
22 Sep - 30 Sep	Ryanair
08 Sep - 18 Sep	Avianca
02 Sep - 23 Sep	Avianca
02 Sep - 18 Sep	Avianca
20 Sep - 05 Oct	TAP
26 Sep - 17 Oct	Norse Atlantic Airways (UK)
17 Sep - 14 Oct	Avianca
26 Sep - 13 Oct	Norse Atlantic Airways (UK)
26 Sep - 31 Oct	Vueling Airlines
02 Sep - 12 Oct	LATAM Airlines Group
18 Sep - 22 Oct	LATAM Airlines Group
18 Sep - 05 Oct	LATAM Airlines Group

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 842€

Return flights