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

Return flights

23 Sep - 28 Oct	TAP
24 Sep - 29 Oct	LATAM Airlines Group
17 Sep - 14 Oct	Azul Airlines
11 Sep - 15 Oct	Ryanair
29 Sep - 14 Oct	TAP
13 Sep - 28 Sep	Azul Airlines
14 Sep - 10 Oct	Azul Airlines
07 Sep - 21 Sep	Azul Airlines
16 Sep - 30 Sep	Ryanair
08 Sep - 23 Sep	Azul Airlines
12 Sep - 27 Sep	Azul Airlines
22 Sep - 29 Sep	Ryanair
10 Sep - 24 Sep	Azul Airlines
14 Sep - 26 Sep	Azul Airlines
05 Sep - 29 Sep	LATAM Airlines Group
18 Sep - 21 Sep	Ryanair
27 Sep - 03 Oct	Ryanair
26 Sep - 03 Oct	Azul Airlines
26 Sep - 02 Oct	TAP

Also check the deals for one-way flights from Lisbon 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 Lisbon to Buenos Aires in September from $1003

Return flights