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

Return flights

04 Dec - 08 Dec	United	direct
11 Dec - 24 Dec	United
29 Dec - 10 Jan	Delta
04 Dec - 07 Dec	United	direct
29 Dec - 10 Jan	United	direct
25 Dec - 31 Dec	Delta
18 Dec - 23 Dec	United
18 Dec - 21 Dec	United
25 Dec - 09 Jan	United
25 Dec - 08 Jan	United
19 Dec - 04 Jan	Air Canada
24 Dec - 08 Jan	United
23 Dec - 30 Dec	Delta
22 Dec - 31 Dec	Delta
20 Dec - 28 Dec	Air Canada
21 Dec - 31 Dec	Delta
25 Dec - 01 Jan	United
19 Dec - 04 Jan	United	direct

Also check the deals for one-way flights from Washington to San Juan 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 Juan in December from $363

Return flights