The cheapest Frankfurt to San Juan return flight on the radar right now is €828, flying with British Airways via one or more connections. It covers departures in November 2026, and every dated link below opens that exact FRA–SJU search on Skyscanner. The price we usually record on this route is €782. Across 49 recorded checks it has ranged between €540 and €1,160. Our sampling points to November 2026 as the cheapest month to fly Frankfurt to San Juan.
Prices are re-checked against Skyscanner automatically, and every one shows when it was last confirmed, so nothing here is older than it looks. Not flying from Frankfurt? We track 53 other departure cities for San Juan, listed at the foot of this page.
Prices like this tend to vanish fast. If it has gone when you look, try the days either side of the dates above, since Frankfurt to San Juan is often still worth booking within a day or two of the fare we found.