$394 Cheap Flights from Boston (BOS) to Kos (KGS)

View $394 flight on Sat, Oct 18, 2025Opens in a new window

Popular airlines from Logan International Airport (BOS) to Kos (KGS-Kos Island Intl.)

Cheap Flights from Boston to Kos (BOS-KGS)

Prices were available within the past 7 days and start at $394 for one-way flights and $535 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Tue, Oct 14 - Thu, Oct 23
BOS
Boston
KGS
Kos
$535 Roundtrip, found 3 days ago
$535
Roundtrip
found 3 days ago
Select United flight, departing Tue, Oct 14 from Boston to Kos, returning Thu, Oct 23, priced at $535 found 3 days ago
Lufthansa
Tue, Oct 28 - Mon, Nov 3
BOS
Boston
KGS
Kos
$540 Roundtrip, found 3 days ago
$540
Roundtrip
found 3 days ago
Select Lufthansa flight, departing Tue, Oct 28 from Boston to Kos, returning Mon, Nov 3, priced at $540 found 3 days ago
United
Tue, Oct 28 - Mon, Nov 3
BOS
Boston
KGS
Kos
$544 Roundtrip, found 3 days ago
$544
Roundtrip
found 3 days ago
Select United flight, departing Tue, Oct 28 from Boston to Kos, returning Mon, Nov 3, priced at $544 found 3 days ago
Air Canada
Tue, Oct 28 - Mon, Nov 3
BOS
Boston
KGS
Kos
$546 Roundtrip, found 3 days ago
$546
Roundtrip
found 3 days ago
Select Air Canada flight, departing Tue, Oct 28 from Boston to Kos, returning Mon, Nov 3, priced at $546 found 3 days ago
Swiss International Air Lines
Mon, Oct 20 - Wed, Oct 29
BOS
Boston
KGS
Kos
$552 Roundtrip, found 3 days ago
$552
Roundtrip
found 3 days ago
Select Swiss International Air Lines flight, departing Mon, Oct 20 from Boston to Kos, returning Wed, Oct 29, priced at $552 found 3 days ago
United
Wed, Oct 15 - Wed, Oct 29
BOS
Boston
KGS
Kos
$558 Roundtrip, found 3 days ago
$558
Roundtrip
found 3 days ago
Select United flight, departing Wed, Oct 15 from Boston to Kos, returning Wed, Oct 29, priced at $558 found 3 days ago
United
Fri, Oct 17 - Thu, Oct 23
BOS
Boston
KGS
Kos
$563 Roundtrip, found 3 days ago
$563
Roundtrip
found 3 days ago
Select United flight, departing Fri, Oct 17 from Boston to Kos, returning Thu, Oct 23, priced at $563 found 3 days ago
Swiss International Air Lines
Sat, Oct 18 - Wed, Oct 29
BOS
Boston
KGS
Kos
$580 Roundtrip, found 3 days ago
$580
Roundtrip
found 3 days ago
Select Swiss International Air Lines flight, departing Sat, Oct 18 from Boston to Kos, returning Wed, Oct 29, priced at $580 found 3 days ago
British Airways
Mon, Oct 13 - Mon, Oct 20
BOS
Boston
KGS
Kos
$580 Roundtrip, found 1 day ago
$580
Roundtrip
found 1 day ago
Select British Airways flight, departing Mon, Oct 13 from Boston to Kos, returning Mon, Oct 20, priced at $580 found 1 day ago
Lufthansa
Fri, Oct 17 - Wed, Oct 29
BOS
Boston
KGS
Kos
$582 Roundtrip, found 3 days ago
$582
Roundtrip
found 3 days ago
Select Lufthansa flight, departing Fri, Oct 17 from Boston to Kos, returning Wed, Oct 29, priced at $582 found 3 days 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 $682
KGS
Kos Island Intl.
CheapestClosest
Average driving time to city center25 min
Flights from $682
Flights from Boston (BOS) to Kos (KGS)
Origin airport
Logan Intl.
Destination airport
Kos Island Intl.
Airlines serving
Austrian Airlines, British Airways, Emirates, Lufthansa, Swiss International Air Lines
Roundtrip price
$535
Distance
4927 mi

Boston to Kos Flights

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

 

The best time to book a flight from Boston to Kos

Sunday is one of the best days to book for cheap flights from Boston 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 Boston 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 Boston to Kos in 2025. You can also book with separate airlines for your outbound and return journeys, from $394 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 Boston 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 Boston 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.

 

Frequently asked questions

How much does a flight from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS) cost?
Snag a cheap one-way flight from $394 or cheap return flight from $535 from Logan Intl. Airport (BOS) 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 Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS)?
October is the least expensive month to fly from BOS to KGS. Avoiding peak travel times is often the key to landing a great deal.
What is the cheapest airline that flies from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS)?
Use the filters on Expedia to compare airlines and find the cheapest carrier that'll take you from BOS to KGS. Then, sort your results by "Price (lowest to highest)" to score a great deal.
How many flights per day from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS)?
Nonstop flights from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS) aren't available daily, so you'll need to take a flight with a layover. Explore your options with Expedia's filters. Enter your travel dates and click on either "1 Stop" or "2+ Stops."
What day of the week has the most flights from BOS to KGS?
You'll generally find Tuesday the quietest day for flights, while Fridays tend to be the busiest.* However this can change from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS)?
To avoid possible delays on the Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS) route, aim to 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 Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS) last-minute?
Holding off until just before your trip to book your flight from BOS to KGS generally means paying more. While you may come across some last-minute deals, they aren't always guaranteed. Be flexible with your travel plans to boost your chances of snagging a bargain.
Is it cheaper to book a BOS to KGS flight and hotel package?
Compared with arranging flights and hotels separately, booking a BOS to KGS flight and hotel package with Expedia could lead to significant savings. Better still, having everything in one place takes the hassle out of travel planning. Just pick your flights and choose from our extensive range of hotels, then customize your trip with other add-ons like car rentals and activities.
Can I cancel or change the date of my flight from Logan Intl. Airport (BOS) to Kos Island Intl. Airport (KGS)?
If you reserved your BOS to KGS flight within the last 24 hours, you may be able to cancel or modify it without any fees. Depending on the airline and the type of fare you purchased, additional charges may apply for changes after 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.

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*Available to One Key members.