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

Return flights

08 Dec - 13 Dec	United
08 Dec - 13 Dec	Avianca	direct
09 Dec - 13 Dec	Avianca	direct
08 Dec - 11 Dec	Avianca	direct
08 Dec - 10 Dec	Copa
12 Dec - 15 Dec	Copa
10 Dec - 17 Dec	Copa
11 Dec - 16 Dec	Avianca	direct
11 Dec - 22 Dec	Copa
11 Dec - 18 Dec	Copa
16 Dec - 17 Jan	Frontier Airlines
24 Dec - 12 Jan	Frontier Airlines
25 Dec - 12 Jan	Avianca
23 Dec - 01 Jan	Southern Airways Express
22 Dec - 01 Jan	Southern Airways Express
25 Dec - 01 Jan	Frontier Airlines
29 Dec - 04 Jan	Frontier Airlines
31 Dec - 04 Jan	Avianca
27 Dec - 01 Jan	Frontier Airlines
25 Dec - 05 Jan	Avianca	direct

Also check the deals for one-way flights from Washington to San Jose 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 San Jose in December from 202€

Return flights