Cheapest one-way flights from Washington to San Juan in September from $127

AirHint found the following cheapest one-way flights from Washington (IAD) to San Juan (SJU) in September 2025 (see full year).

One-Way flights

19 Sep Frontier Airlines
21 Sep Frontier Airlines
21 Sep United direct
27 Sep United direct
22 Sep United
26 Sep United
17 Sep United
25 Sep Frontier Airlines
01 Sep United direct
05 Sep Frontier Airlines

Also check the deals for return flights from Washington to San Juan in September.

Skyscanner

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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