Altius recorded 276 priced readings of nonstop business-class round trips from Boston (BOS) to Barcelona (BCN) booked 30 days out, across 120 departure dates between 2026-05-20 and 2026-09-17. Observed fares ran from US$2,709 to US$15,405. The lowest fare Altius scored on this window was US$2,709 for a 2026-07-21 departure, seen on 2026-06-21 — STRONG at the time, 18.5% below the US$3,324 this route was typically running that day.
A fare can move between our two readings of the same day, most often on the days furthest below typical. Where a day's two readings differ enough to matter, the chart marks that day and both readings can be read separately.