Average nonstop flight time from Boston Logan International Airport (BOS) to Barcelona–El Prat Airport (BCN), when offered seasonally, is roughly 7 hours 30 minutes to 8 hours 30 minutes westbound or eastbound depending on winds. More commonly in September, one-stop itineraries via Madrid (MAD), London Heathrow (LHR), Dublin (DUB), or continental hubs add 2–5 hours of connection time, yielding total door-to-door durations of 10–15 hours. Typical transatlantic departure windows from BOS include late morning to evening flights aimed at convenient European arrival times. For an optimized itinerary, target early-morning departures from Boston or overnight red-eyes that arrive in Barcelona in the afternoon local time. Book with airlines that publish consistent September schedules and check timetable updates before departure.