AirHint found the following cheapest return flights from Washington (IAD) to Buenos Aires (AEP) in December 2025 (see full year).

Return flights

01 Dec - 10 Dec	Avianca
01 Dec - 09 Dec	Avianca
01 Dec - 14 Dec	Avianca
12 Dec - 19 Dec	Frontier Airlines
31 Dec - 16 Jan	Avianca
30 Dec - 14 Jan	Avianca
24 Dec - 30 Dec	Avianca
26 Dec - 31 Dec	Frontier Airlines
24 Dec - 05 Jan	Avianca
02 Dec - 04 Dec	Copa
30 Dec - 15 Jan	Avianca
24 Dec - 04 Jan	Avianca
30 Dec - 09 Jan	Avianca
19 Dec - 09 Jan	Frontier Airlines
21 Dec - 08 Jan	Frontier Airlines
29 Dec - 07 Jan	Avianca
11 Dec - 14 Dec	Avianca
14 Dec - 03 Jan	Frontier Airlines
19 Dec - 27 Dec	Avianca

Also check the deals for one-way flights from Washington to Buenos Aires in December.

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 Washington to Buenos Aires in December from $622

Return flights