Altius recorded 285 priced readings of nonstop business-class round trips from Boston (BOS) to Istanbul (IST) booked 30 days out, across 125 departure dates between 2026-05-20 and 2026-10-04. Observed fares ran from US$4,641 to US$10,701. The lowest fare Altius scored on this window was US$4,641 for a 2026-07-09 departure, seen on 2026-06-09 — STRONG at the time, 21.9% below the US$5,942 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.