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

Return flights

02 Sep - 29 Sep	Ryanair
25 Sep - 13 Oct	Ryanair
25 Sep - 17 Oct	Ryanair
04 Sep - 18 Sep	Ryanair
07 Sep - 11 Sep	Ryanair
16 Sep - 15 Oct	Iberia Express
13 Sep - 19 Sep	Ryanair
12 Sep - 22 Sep	TAP
02 Sep - 09 Sep	Ryanair
08 Sep - 15 Sep	TAP
12 Sep - 15 Sep	TAP
25 Sep - 06 Oct	LATAM Airlines Group
27 Sep - 30 Sep	Ryanair
25 Sep - 11 Oct	LATAM Airlines Group
03 Sep - 30 Sep	LATAM Airlines Group
08 Sep - 04 Oct	British Airways
18 Sep - 02 Oct	LATAM Airlines Group
17 Sep - 13 Oct	Iberia
17 Sep - 15 Oct	Iberia
26 Sep - 18 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 $1064

Return flights