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Cheap flights from Boston to Kos from $325

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Boston to Kos departing on 9/18. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Boston to Kos

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
8:50 pm - 10:05 pmBOS  Boston Logan Intl-KGS Kos
18h 15m2 stops Reykjavik Keflavik Intl Glasgow Intl
Multiple Airlines Logo
12:10 am - 1:40 pmKGS  Kos-BOS Boston Logan Intl
44h 30m3 stops London Gatwick Montreal Pierre Elliott Trudeau Intl Toronto Island
$909Multiple Airlines
Mon, Sep 21 - Sun, Sep 27
Multiple Airlines Logo
8:50 pm - 10:05 pmBOS  Boston Logan Intl-KGS Kos
18h 15m2 stops Reykjavik Keflavik Intl Glasgow Intl
Multiple Airlines Logo
12:10 am - 9:26 pmKGS  Kos-BOS Boston Logan Intl
28h 16m2 stops London Gatwick Montreal Pierre Elliott Trudeau Intl
$968Multiple Airlines
Mon, Sep 21 - Sun, Sep 27
Multiple Airlines Logo
5:40 pm - 10:10 pmBOS  Boston Logan Intl-KGS Kos
21h 30m3 stops Kastrup Copenhagen Brussels Bruxelles-National Athens Eleftherios V.
Multiple Airlines Logo
12:20 pm - 3:35 pmKGS  Kos-BOS Boston Logan Intl
34h 15m3 stops Brussels Bruxelles-National Stockholm Arlanda Kastrup Copenhagen
$968Multiple Airlines
Mon, Sep 21 - Mon, Sep 28
Multiple Airlines Logo
9:40 pm - 7:40 pmBOS  Boston Logan Intl-KGS Kos
15h 00m1 stop Zurich
Multiple Airlines Logo
11:00 pm - 4:10 pmKGS  Kos-BOS Boston Logan Intl
24h 10m2 stops Milan Malpensa Madrid Barajas
$988Multiple Airlines
Mon, Sep 21 - Mon, Sep 28
SWISS Logo
9:40 pm - 7:40 pmBOS  Boston Logan Intl-KGS Kos
15h 00m1 stop Zurich
SWISS Logo
11:00 am - 7:55 pmKGS  Kos-BOS Boston Logan Intl
15h 55m1 stop Zurich
$1,006SWISS
Mon, Sep 21 - Mon, Sep 28
Multiple Airlines Logo
3:35 pm - 12:35 amBOS  Boston Logan Intl-KGS Kos
26h 00m3 stops Montreal Pierre Elliott Trudeau Intl London Heathrow Athens Eleftherios V.
Multiple Airlines Logo
12:10 am - 4:05 pmKGS  Kos-BOS Boston Logan Intl
46h 55m3 stops London Gatwick Montreal Pierre Elliott Trudeau Intl Toronto Pearson Intl
$1,017Multiple Airlines
Tue, Sep 1 - Sun, Sep 6
Multiple Airlines Logo
4:45 pm - 9:55 pmBOS  Boston Logan Intl-KGS Kos
22h 10m3 stops Frankfurt am Main Rome Fiumicino Athens Eleftherios V.
Multiple Airlines Logo
11:40 pm - 2:45 pmKGS  Kos-BOS Boston Logan Intl
22h 05m2 stops Rome Fiumicino Frankfurt am Main
$1,034Multiple Airlines
Tue, Sep 1 - Mon, Sep 7
Multiple Airlines Logo
3:55 pm - 8:20 pmBOS  Boston Logan Intl-KGS Kos
21h 25m2 stops Ottawa London Gatwick
Multiple Airlines Logo
12:10 am - 6:35 pmKGS  Kos-BOS Boston Logan Intl
25h 25m2 stops London Gatwick Toronto Pearson Intl
$1,108Multiple Airlines
Tue, Sep 1 - Sun, Sep 6
Multiple Airlines Logo
5:05 pm - 9:55 pmBOS  Boston Logan Intl-KGS Kos
21h 50m2 stops Rome Fiumicino Athens Eleftherios V.
Multiple Airlines Logo
11:40 pm - 1:40 pmKGS  Kos-BOS Boston Logan Intl
21h 00m1 stop Rome Fiumicino
$1,167Multiple Airlines
Tue, Sep 1 - Mon, Sep 7
SWISS Logo
9:40 pm - 7:40 pmBOS  Boston Logan Intl-KGS Kos
15h 00m1 stop Zurich
SWISS Logo
8:30 pm - 3:10 pmKGS  Kos-BOS Boston Logan Intl
25h 40m1 stop Zurich
$1,590SWISS
Mon, Aug 24 - Tue, Sep 8

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SWISS flights from Boston to Kos

Our best SWISS deals on Boston to Kos flight tickets
SWISS
Sep 21
BOS9:40 pmBoston Logan Intl
15h 00m
1 stop
KGS7:40 pmKos
Sep 28
KGS11:00 amKos
15h 55m
1 stop
BOS7:55 pmBoston Logan Intl
$1,006
SWISS
Aug 24
BOS9:40 pmBoston Logan Intl
15h 00m
1 stop
KGS7:40 pmKos
Sep 8
KGS8:30 pmKos
25h 40m
1 stop
BOS3:10 pmBoston Logan Intl
$1,590
SWISS
Aug 25
BOS5:10 pmBoston Logan Intl
19h 45m
1 stop
KGS7:55 pmKos
Sep 8
KGS8:30 pmKos
30h 25m
1 stop
BOS7:55 pmBoston Logan Intl
$1,592

Lufthansa flights from Boston to Kos

Our best Lufthansa deals on Boston to Kos flight tickets
Lufthansa
Aug 25
BOS7:23 pmBoston Logan Intl
16h 42m
2 stops
KGS7:05 pmKos
Sep 9
KGS1:30 pmKos
13h 40m
1 stop
BOS8:10 pmBoston Logan Intl
$1,606
Lufthansa
Aug 24
BOS2:28 pmBoston Logan Intl
39h 12m
2 stops
KGS12:40 pmKos
Sep 9
KGS1:30 pmKos
13h 40m
1 stop
BOS8:10 pmBoston Logan Intl
$1,651
Lufthansa
Aug 24
BOS7:23 pmBoston Logan Intl
34h 17m
2 stops
KGS12:40 pmKos
Sep 9
KGS7:55 pmKos
35h 04m
2 stops
BOS11:59 pmBoston Logan Intl
$1,658

momondo Fare Finder

 
Customize your flight search to find flights from Boston to Kos that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated August 8, 2026.
Use the filters below to find and compare flights from Boston to Kos that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 9/21

8:50 pm-10:05 pm

2 stops18h 15m

Kos

Sun 9/27

12:10 am-1:40 pm

3 stops44h 30m

$909

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 9/21

8:50 pm-10:05 pm

2 stops18h 15m

Kos

Sun 9/27

12:10 am-9:26 pm

2 stops28h 16m

$968

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 9/21

5:40 pm-10:10 pm

3 stops21h 30m

Kos

Mon 9/28

12:20 pm-3:35 pm

3 stops34h 15m

$968

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 9/21

9:40 pm-7:40 pm

1 stop15h 00m

Kos

Mon 9/28

11:00 pm-4:10 pm

2 stops24h 10m

$988
Quickest round-trip

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 9/21

9:40 pm-7:40 pm

1 stop15h 00m

Kos

Mon 9/28

11:00 am-7:55 pm

1 stop15h 55m

$1,006

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Tue 9/1

3:35 pm-12:35 am

3 stops26h 00m

Kos

Sun 9/6

12:10 am-4:05 pm

3 stops46h 55m

$1,017

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Tue 9/1

4:45 pm-9:55 pm

3 stops22h 10m

Kos

Mon 9/7

11:40 pm-2:45 pm

2 stops22h 05m

$1,034

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Tue 9/1

3:55 pm-8:20 pm

2 stops21h 25m

Kos

Sun 9/6

12:10 am-6:35 pm

2 stops25h 25m

$1,108

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Tue 9/1

5:05 pm-9:55 pm

2 stops21h 50m

Kos

Mon 9/7

11:40 pm-1:40 pm

1 stop21h 00m

$1,167

BostonKos

BOS Boston Logan Intl - KGS Kos

BOSKGS

Boston Logan Intl

Mon 8/24

9:40 pm-7:40 pm

1 stop15h 00m

Kos

Tue 9/8

8:30 pm-3:10 pm

1 stop25h 40m

$1,590

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
1
2

When to book flights from Boston to Kos

Are you open to changing your travel dates? Check out the ideal times to fly from Boston to Kos according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Boston to Kos (BOS to KGS) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Boston to Kos

Fastest flight time

19h 20m

Direct flights

None
The fastest flight from Boston to Kos takes 19h 20m
There are no direct flights from Boston to Kos. There are no popular flight routes from Boston to Kos.
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Frequently asked questions about flying from Boston to Kos

  • How far is Boston Logan Intl to Kos by plane?

    The distance between Boston Logan Intl and Kos is about 4930.9 mi. By plane, this route typically takes 19h 20m.

  • When did momondo last update prices for flights from Boston Logan Intl Airport to Kos Airport?

    Prices for flights from Boston Logan Intl Airport to Kos Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Boston Logan Intl Airport to Kos Airport?

  • How old do you have to be to fly from Boston Logan Intl Airport to Kos Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Boston Logan Intl Airport to Kos Airport.

  • What documentation or ID do you need to fly to Kos Airport?

    The necessary travel and health documents for your Kos Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from Boston to Kos?

Best airlines flying from Boston to Kos

Compare and see reviews for airlines that fly from Boston to Kos with momondo
Airline
Rating
Free Cancellation
Price
SWISSPriceFrom $967Free CancellationRating
7.5
2,031 reviews
Search SWISS flights

Frequently asked questions about flying from Boston to Kos

  • How do I get Price Alerts for flights from Boston to Kos?

    Price Alerts will notify you by email when the price for flights to Kos from Boston decreases. To activate this, select your desired travel dates and search for offers. While browsing through offers you’ll see the Price Alert widget toggle. Click it to turn on notifications.

  • How can I save money on flights from Boston to Kos with momondo?

    Leverage our AI within our “Price Forecast” tool, which predicts if it’s better to book now or wait until prices decrease. You can strategically pick the best days to fly and save money on your trip by using our “Price Calendar” tool. “Explore” shows an overview of how much it costs to fly to anywhere from a selected city or airport. Our “Discover” content is a great option for travel inspiration and money-saving tips, while “Price Alerts” will update you when prices change, so you can book when fares are right.

  • How does momondo find its flight prices?

    momondo shows deals across 700+ competitors all at once. momondo is active in 30 international markets, so you can have access to a wide range of options from airlines and OTAs alike.

Traveling to a place near Kos?

Book flights to Kos if you plan to visit one of these locations
Marmari
Kardamena

Why use momondo?

Why should I use momondo to find a flight deal from Boston to Kos?

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to Kos from Boston.

Can I find flights from Boston to Kos with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to Kos from Boston with this policy.

How can momondo help me find flights from Boston to Kos?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Boston to Kos.

I’m not ready to book a flight from Boston to Kos right now. Can momondo alert me if prices change?

If you are not ready to book a flight from Boston to Kos now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Kos and let you know when they change.

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