AirHint found the following cheapest return flights from Washington (IAD) to San Jose (SJO) in August 2025 (see full year).

Return flights

22 Aug - 01 Sep	Avianca
22 Aug - 28 Aug	United
12 Aug - 14 Aug	United
15 Aug - 25 Aug	American Airlines
20 Aug - 25 Aug	American Airlines
20 Aug - 27 Aug	American Airlines
15 Aug - 25 Aug	Avianca	direct
05 Aug - 26 Aug	Avianca
06 Aug - 27 Aug	Copa
10 Aug - 14 Aug	Avianca
22 Aug - 28 Aug	Avianca	direct
28 Aug - 02 Sep	Avianca
29 Aug - 07 Sep	Avianca
05 Aug - 01 Sep	Avianca
11 Aug - 01 Sep	Avianca
25 Aug - 01 Sep	Avianca

Also check the deals for one-way flights from Washington to San Jose in August.

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 San Jose in August from $249

Return flights