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

Return flights

09 Sep - 21 Oct	LATAM Airlines Group
14 Sep - 30 Sep	TAP
08 Sep - 06 Oct	LATAM Airlines Group
01 Sep - 30 Oct	LATAM Airlines Group
24 Sep - 08 Oct	LATAM Airlines Group
18 Sep - 02 Oct	Air Canada
18 Sep - 25 Sep	LATAM Airlines Group
03 Sep - 30 Sep	LATAM Airlines Group
15 Sep - 28 Sep	Air Canada
17 Sep - 24 Sep	LATAM Airlines Group
07 Sep - 21 Sep	British Airways
19 Sep - 21 Sep	British Airways
19 Sep - 05 Oct	British Airways
26 Sep - 30 Oct	British Airways
15 Sep - 22 Sep	Air Canada
23 Sep - 24 Oct	LATAM Airlines Group
19 Sep - 28 Sep	British Airways
11 Sep - 26 Sep	British Airways
26 Sep - 31 Oct	British Airways
22 Sep - 03 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 $1166

Return flights