Every Washington–San Juan fare we track, measured against the route's typical price whenever there is enough cached history to build one. Subscribe in any RSS reader for free single-route price alerts — no account, no email needed.https://flight.dealsen-ushttps://flight.deals/flights/washington-to-san-juan/#2026-09-17-2026-09-21-F9https://flight.deals/flights/washington-to-san-juan/#2026-09-17-2026-09-21-F9WAS → SJU round-trip on Frontier Airlines, 2026-09-17 to 2026-09-21 (4 nights). Cached fare $205 vs typical $325.Sun, 30 Aug 2026 05:03:17 GMT