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

Return flights

14 May - 17 May	Frontier Airlines
11 May - 15 May	Frontier Airlines
08 May - 15 May	Frontier Airlines
11 May - 15 May	United	direct
05 May - 12 May	United	direct
12 May - 15 May	United	direct
18 May - 23 May	United	direct
12 May - 16 May	United
06 May - 12 May	United
13 May - 20 May	United
18 May - 01 Jun	Frontier Airlines
18 May - 01 Jun	United	direct
29 May - 03 Jun	United
24 May - 01 Jun	United

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

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.

Book a cheap hotel in San Juan

Cheap car rent in San Juan

Cheapest return flights from Washington to San Juan in May from 162€

Return flights