Altius recorded 310 priced readings of nonstop business-class round trips from Boston (BOS) to Lisbon (LIS) booked 30 days out, across 139 departure dates between 2026-05-20 and 2026-10-05. Observed fares ran from US$3,301 to US$12,481. The lowest fare Altius scored on this window was US$3,301 for a 2026-07-29 departure, seen on 2026-06-29 — DECENT at the time, 10.3% below the US$3,680 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.