Shoulder-Season Flight Deals to Lisbon

Lisbon is one of the easier European capitals to score cheap flights to from both US East Coast hubs and most of Western Europe. The sweet spot is late April–early June and late September–October: weather is still great, prices drop 30–50% from peak summer, and TAP regularly runs sub-$400 round-trips from JFK/BOS/EWR. Set fare alerts on Google Flights for a 60-day window and be flexible by ±3 days, midweek departures consistently beat weekends.