AirHint found the following cheapest return flights from Washington (IAD) to San Juan (SJU) in April 2026 (see full year).

Return flights

11 Apr - 18 Apr	Frontier Airlines
11 Apr - 16 Apr	Frontier Airlines
11 Apr - 19 Apr	Frontier Airlines
19 Apr - 23 Apr	Frontier Airlines
12 Apr - 18 Apr	Frontier Airlines
09 Apr - 16 Apr	Frontier Airlines
20 Apr - 25 Apr	Frontier Airlines
12 Apr - 19 Apr	Frontier Airlines
18 Apr - 25 Apr	Frontier Airlines
13 Apr - 18 Apr	Frontier Airlines
29 Apr - 02 May	Delta
30 Apr - 03 May	Frontier Airlines
30 Apr - 02 May	Delta
29 Apr - 03 May	United
30 Apr - 04 May	United	direct

Also check the deals for one-way flights from Washington to San Juan in April.

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 April from 137€

Return flights