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

Return flights

14 Sep - 18 Oct	Azul Airlines
10 Sep - 15 Oct	Azul Airlines
14 Sep - 15 Oct	Azul Airlines
03 Sep - 28 Oct	Azul Airlines
11 Sep - 23 Oct	Avianca
09 Sep - 16 Oct	Azul Airlines
16 Sep - 14 Oct	Azul Airlines
08 Sep - 26 Sep	Avianca
07 Sep - 30 Sep	Avianca
10 Sep - 13 Oct	Azul Airlines
08 Sep - 30 Sep	Avianca
09 Sep - 29 Sep	Azul Airlines
09 Sep - 30 Sep	Azul Airlines
06 Sep - 26 Sep	Azul Airlines
15 Sep - 15 Oct	Azul Airlines
09 Sep - 07 Oct	Azul Airlines
10 Sep - 29 Sep	Azul Airlines
01 Sep - 30 Sep	Azul Airlines
07 Sep - 23 Sep	Avianca
11 Sep - 28 Sep	Avianca

Also check the deals for one-way flights from Madrid 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 Madrid to Buenos Aires in September from $867

Return flights