$664 Cheap Flights from Washington (IAD) to Kos (KGS)

View $664 flight on Sun, Oct 19, 2025Opens in a new window

Popular airlines from Washington Dulles Intl. Airport (IAD) to Kos (KGS-Kos Island Intl.)

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Cheap Flights from Washington to Kos (IAD-KGS)

Prices were available within the past 7 days and start at $664 for one-way flights and $1,080 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,080 Roundtrip, found 8 hours ago
$1,080
Roundtrip
found 8 hours ago
Select United flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,080 found 8 hours ago
Air Canada
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,087 Roundtrip, found 8 hours ago
$1,087
Roundtrip
found 8 hours ago
Select Air Canada flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,087 found 8 hours ago
United
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,096 Roundtrip, found 8 hours ago
$1,096
Roundtrip
found 8 hours ago
Select United flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,096 found 8 hours ago
United
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,103 Roundtrip, found 8 hours ago
$1,103
Roundtrip
found 8 hours ago
Select United flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,103 found 8 hours ago
Air Canada
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,105 Roundtrip, found 8 hours ago
$1,105
Roundtrip
found 8 hours ago
Select Air Canada flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,105 found 8 hours ago
Air Canada
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,107 Roundtrip, found 8 hours ago
$1,107
Roundtrip
found 8 hours ago
Select Air Canada flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,107 found 8 hours ago
Lufthansa
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,107 Roundtrip, found 8 hours ago
$1,107
Roundtrip
found 8 hours ago
Select Lufthansa flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,107 found 8 hours ago
Air Canada
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,107 Roundtrip, found 8 hours ago
$1,107
Roundtrip
found 8 hours ago
Select Air Canada flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,107 found 8 hours ago
Swiss International Air Lines
Fri, Oct 17 - Wed, Oct 22
IAD
Washington
KGS
Kos
$1,281 Roundtrip, found 8 hours ago
$1,281
Roundtrip
found 8 hours ago
Select Swiss International Air Lines flight, departing Fri, Oct 17 from Washington to Kos, returning Wed, Oct 22, priced at $1,281 found 8 hours ago
British Airways
Sun, Oct 19 - Thu, Oct 23
IAD
Washington
KGS
Kos
$2,000 Roundtrip, found 17 hours ago
$2,000
Roundtrip
found 17 hours ago
Select British Airways flight, departing Sun, Oct 19 from Washington to Kos, returning Thu, Oct 23, priced at $2,000 found 17 hours ago

Alternative airports near Kos

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Kos Island Intl. KGS. Cheapest and Closest option available. Average driving time to city center is 25 minutes. Flights from $1,884
KGS
Kos Island Intl.
CheapestClosest
Average driving time to city center25 min
Flights from $1,884

Frequently asked questions

How much does a flight from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS) cost?
Grab a cheap one-way flight from $664 or cheap return flight from $1,080 from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight deals on this route.
What is the cheapest month to fly from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS)?
Planning your getaway for October can help you save, as it's the cheapest month for flights between IAD and KGS. You'll often find the lowest prices during the off-season.
What is the cheapest airline that flies from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS)?
To find the cheapest airline flying from IAD to KGS, use Expedia's filter tool. Tailor your search based on what matters most to you, such as preferred carriers and ideal departure window. You can then sort your results by "Price (lowest to highest)" to see the cheapest flights first.
How many flights per day from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS)?
There aren't any daily direct flights from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS). But you can book flights with layovers. Filter your search results on Expedia to include one or two stops, and you'll be soaring above the clouds in no time.
What day of the week has the most flights from IAD to KGS?
Usually you'll find the greatest selection of flight options on a Friday. Tuesdays are often the quietest.* But this can change depending on the airline, time of year 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 Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS)?
Book a flight from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS) that takes off before 3 PM to reduce the risk of cancellations. Departures later than this have a 22% higher chance of being canceled, on average.**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 Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS) last-minute?
Holding off until just before your departure to book your flight from IAD to KGS often results in higher prices. While you might find some last-minute deals, they aren't always guaranteed. Allow some flexibility in your schedule to boost your chances of landing a bargain.
Is it cheaper to book an IAD to KGS flight and hotel package?
You can save money by booking an IAD to KGS flight and hotel package compared to booking separately. In fact, you could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one place. Once you've selected your ideal flights and accommodations, you can add extras such as car rentals, activities and tours.
Can I cancel or change the date of my flight from Washington Dulles Intl. Airport (IAD) to Kos Island Intl. Airport (KGS)?
Usually, it's possible to reschedule or cancel your IAD to KGS flight. However, if it's been more than 24 hours since booking, additional charges may apply. Refer to your airline's policies in your itinerary to see what changes are allowed and whether any costs are involved. You'll also find more details on our Customer Service portal.

Travel information

Travel information

Origin airport
Washington Dulles Intl.
Destination airport
Kos Island Intl.
Airlines serving
Austrian Airlines, British Airways, Lufthansa, Swiss International Air Lines
Roundtrip price
$1,080
Distance
5338 mi

Book with confidence

Book with confidence

Washington to Kos Flights

The cheapest times to fly from Washington to Kos

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 Washington to Kos are during the month of October. You can find some of the cheapest flights from Washington to Kos with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Washington to Kos

Sunday is one of the best days to book for cheap flights from Washington to Kos: 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 Washington to Kos

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 Washington to Kos in 2025. You can also book with separate airlines for your outbound and return journeys, from $664 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 Washington to Kos 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 Washington to Kos 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.

 

Washington to Kos Flights

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*Available to One Key members.