$278 Cheap Flights from Portsmouth (PSM) to Washington (IAD)

View $278 flight on Sun, Dec 14, 2025Opens in a new window

Popular airlines from Portsmouth, NH (PSM-Portsmouth Intl.) to Washington Dulles Intl. Airport (IAD)

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Cheap Flights from Portsmouth to Washington (PSM-IAD)

Prices were available within the past 7 days and start at $278 for one-way flights and $747 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Breeze Airways
Sun, Dec 14 - Fri, Dec 19
PSM
Portsmouth
IAD
Washington
$747 Roundtrip, found 6 days ago
$747
Roundtrip
found 6 days ago
Select Breeze Airways flight, departing Sun, Dec 14 from Portsmouth to Washington, returning Fri, Dec 19, priced at $747 found 6 days ago

Frequently asked questions

How much does a flight from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD) cost?
Lock in a cheap one-way flight from $278 or cheap return flight from $747 from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight deals on this route.
What is the cheapest month to fly from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
Flying in December is a great way to save, as it's the cheapest month for flights between PSM and IAD. You'll usually find the lowest fares during off-peak months.
Which airlines fly direct from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
There are no direct routes from Portsmouth, NH (PSM-Portsmouth Intl.) to Washington Dulles Intl. Airport (IAD). However, you can find other airports with nonstop flights. Board your plane at Logan Intl. Airport (BOS) and travel straight to Washington without layovers.
What is the cheapest airline that flies from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
Use the filters on Expedia to compare airlines and find the cheapest carrier that'll fly you from PSM to IAD. Then, sort your results by "Price (lowest to highest)" to snag the best deal available.
How many flights per day from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
There are no daily direct flights from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD). But you can opt for flights with layovers. Filter your search results on Expedia to include one or more stops, and you'll be soaring above the clouds in no time at all.
What day of the week has the most flights from PSM to IAD?
Typically you'll find the largest variety of flight choices on a Friday. Tuesdays tend to be the quietest.* But this can vary depending on the season, airline and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
To avoid potential delays on the Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD) route, fly before 3 PM. Departures after this hour are 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD) last-minute?
Last-minute fares from PSM to IAD are typically more expensive. To lock in the lowest rates, start searching for flights well ahead of time. That said, if you can play around with your travel dates, you may score a cheap fare just before your departure.
Is it cheaper to book a PSM to IAD flight and hotel package?
Compared with arranging hotels and flights separately, booking a PSM to IAD flight and hotel package with Expedia could lead to significant savings. Better still, having everything in one place will take the hassle out of travel planning. Just secure your flights and choose from our wide range of hotels, then personalize your trip with other add-ons like car rentals and activities.
Can I cancel or change the date of my flight from Portsmouth Intl. Airport (PSM) to Washington Dulles Intl. Airport (IAD)?
If you booked your PSM to IAD flight in the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of fare you purchased, additional charges may apply for changes beyond that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, go to our Customer Service portal for more information.

Travel information

Origin airport
Portsmouth Intl.
Destination airport
Washington Dulles Intl.
Roundtrip price
$746
Distance
447 mi

Book with confidence

Portsmouth to Washington Flights

The cheapest times to fly from Portsmouth to Washington

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Portsmouth to Washington are during the month of December. You can find some of the cheapest flights from Portsmouth to Washington with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Portsmouth to Washington

Sunday is one of the best days to book for cheap flights from Portsmouth to Washington: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Portsmouth to Washington

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Portsmouth to Washington in 2025. You can also book with separate airlines for your outbound and return journeys, from $278 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Portsmouth to Washington flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Portsmouth to Washington airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Portsmouth to Washington Flights

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*Available to One Key members.