Cheap Flights from Washington (IAD) to Lisbon (LIS) from HK$4,352~

Within the past 7 days on Expedia, for flights departing within the next year, the lowest price available for a round-trip flight from IAD to Lisbon/Portela Airport was HK$7,640. Fares this good don't last long, so make sure you book yours today. Prices and availability are subject to change. Additional terms apply.

This differs from airline to airline, as each has its own set of terms and conditions. Visit the Customer Service Portal, where you'll find simple instructions on how to cancel online.

Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for IAD to LIS flights, you'll see a "no change fees" filter for you to select.

You'll have 5,800 kilometers to cover on the long-haul Chantilly to Lisbon District route. Dress in layers of comfortable clothes and consider taking a pair of noise-canceling earphones.

Flying directly from IAD to LIS is simple with TAP Portugal (TP). This popular airline operates 30 flights every month.

Flight prices fluctuate, so there are no guarantees. While last-minute flight deals between IAD and Humberto Delgado Airport (LIS) are possible, it's also a good idea to keep a close eye on prices well before you fly. In fact, some airlines advertise their prices up to a year ahead of the departure date. Expedia is continuously updating the best airfare bargains around, so keep checking back and be ready to lock in your seat when fare prices drop.