$638 Cheap Flights from Boston (BOS) to Kos (KGS)

View $638 flight on Mon, Oct 27, 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 $638 for one-way flights and $926 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Air Canada
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$926 Roundtrip, found 5 days ago
$926
Roundtrip
found 5 days ago
Select Air Canada flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $926 found 5 days ago
Swiss International Air Lines
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$945 Roundtrip, found 5 days ago
$945
Roundtrip
found 5 days ago
Select Swiss International Air Lines flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $945 found 5 days ago
Air Canada
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$998 Roundtrip, found 5 days ago
$998
Roundtrip
found 5 days ago
Select Air Canada flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $998 found 5 days ago
Swiss International Air Lines
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$1,017 Roundtrip, found 5 days ago
$1,017
Roundtrip
found 5 days ago
Select Swiss International Air Lines flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $1,017 found 5 days ago
Air Canada
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$1,039 Roundtrip, found 5 days ago
$1,039
Roundtrip
found 5 days ago
Select Air Canada flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $1,039 found 5 days ago
Swiss International Air Lines
Mon, Oct 27 - Mon, Nov 3
BOS
Boston
KGS
Kos
$1,058 Roundtrip, found 5 days ago
$1,058
Roundtrip
found 5 days ago
Select Swiss International Air Lines flight, departing Mon, Oct 27 from Boston to Kos, returning Mon, Nov 3, priced at $1,058 found 5 days ago
Swiss International Air Lines
Wed, Aug 5 - Wed, Aug 19
BOS
Boston
KGS
Kos
$1,112 Roundtrip, found 6 days ago
$1,112
Roundtrip
found 6 days ago
Select Swiss International Air Lines flight, departing Wed, Aug 5 from Boston to Kos, returning Wed, Aug 19, priced at $1,112 found 6 days ago
Brussels Airlines
Wed, Aug 5 - Wed, Aug 19
BOS
Boston
KGS
Kos
$1,138 Roundtrip, found 6 days ago
$1,138
Roundtrip
found 6 days ago
Select Brussels Airlines flight, departing Wed, Aug 5 from Boston to Kos, returning Wed, Aug 19, priced at $1,138 found 6 days ago
British Airways
Thu, Jun 18 - Wed, Jun 24
BOS
Boston
KGS
Kos
$1,404 Roundtrip, found 3 days ago
$1,404
Roundtrip
found 3 days ago
Select British Airways flight, departing Thu, Jun 18 from Boston to Kos, returning Wed, Jun 24, priced at $1,404 found 3 days ago
Lufthansa
Thu, Oct 30 - Mon, Nov 10
BOS
Boston
KGS
Kos
$1,611 Roundtrip, found 2 days ago
$1,611
Roundtrip
found 2 days ago
Select Lufthansa flight, departing Thu, Oct 30 from Boston to Kos, returning Mon, Nov 10, priced at $1,611 found 2 days ago

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 $638 or cheap return flight from $926 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.

Travel information

Origin airport
Logan Intl.
Destination airport
Kos Island Intl.
Roundtrip price
$925
Distance
4927 mi

Book with confidence

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 $638 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.

 

Boston to Kos Flights

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*Available to One Key members.