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Cheap flights from Washington, D.C. to Ko Samui from $629

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Washington, D.C. to Ko Samui departing on 9/3. 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

Find the cheapest flights from Washington, D.C. to Ko Samui

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
3:10 pm - 10:30 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
32h 20m2 stops Abu Dhabi Zayed Intl Phuket City
Multiple Airlines Logo
5:25 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
27h 20m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,057Multiple Airlines
Mon, Oct 5 - Thu, Oct 15
Multiple Airlines Logo
3:10 pm - 7:30 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
29h 20m2 stops Abu Dhabi Zayed Intl Bangkok Suvarnabhumi
Multiple Airlines Logo
5:35 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
27h 10m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,067Multiple Airlines
Thu, Sep 3 - Tue, Sep 15
Multiple Airlines Logo
3:10 pm - 9:20 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
31h 10m2 stops Abu Dhabi Zayed Intl Bangkok Suvarnabhumi
Multiple Airlines Logo
5:50 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
26h 55m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,067Multiple Airlines
Fri, Sep 4 - Tue, Sep 15
Multiple Airlines Logo
3:10 pm - 8:15 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
30h 05m2 stops Abu Dhabi Zayed Intl Bangkok Suvarnabhumi
Multiple Airlines Logo
11:25 am - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
33h 20m2 stops Phuket City Abu Dhabi Zayed Intl
$1,073Multiple Airlines
Thu, Sep 17 - Thu, Sep 24
Multiple Airlines Logo
3:10 pm - 7:10 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
29h 00m2 stops Abu Dhabi Zayed Intl Bangkok Suvarnabhumi
Multiple Airlines Logo
2:30 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
30h 15m2 stops Phuket City Abu Dhabi Zayed Intl
$1,073Multiple Airlines
Fri, Sep 4 - Mon, Sep 14
Multiple Airlines Logo
3:10 pm - 8:25 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
30h 15m2 stops Abu Dhabi Zayed Intl Phuket City
Multiple Airlines Logo
5:50 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
26h 55m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,073Multiple Airlines
Wed, Sep 16 - Wed, Sep 23
Multiple Airlines Logo
3:10 pm - 8:25 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
30h 15m2 stops Abu Dhabi Zayed Intl Phuket City
Multiple Airlines Logo
5:50 pm - 9:45 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
26h 55m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,074Multiple Airlines
Wed, Sep 16 - Wed, Sep 23
Multiple Airlines Logo
3:35 pm - 10:40 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
32h 05m2 stops Abu Dhabi Zayed Intl Phuket City
Multiple Airlines Logo
4:30 pm - 9:05 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
28h 35m2 stops Bangkok Suvarnabhumi Abu Dhabi Zayed Intl
$1,080Multiple Airlines
Mon, Oct 26 - Mon, Nov 2
Multiple Airlines Logo
1:15 pm - 7:10 amIAD  Washington, D.C. Dulles Intl-USM Ko Samui
30h 55m2 stops Incheon Intl Bangkok Suvarnabhumi
Multiple Airlines Logo
5:00 pm - 11:05 amUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
53h 05m3 stops Krabi Bangkok Suvarnabhumi Incheon Intl
$1,134Multiple Airlines
Sun, Sep 20 - Sun, Sep 27
EVA Air Logo
1:15 am - 3:25 pmIAD  Washington, D.C. Dulles Intl-USM Ko Samui
27h 10m2 stops Taipei City Taiwan Taoyuan Intl Bangkok Suvarnabhumi
EVA Air Logo
6:25 pm - 10:00 pmUSM  Ko Samui-IAD Washington, D.C. Dulles Intl
38h 35m2 stops Bangkok Suvarnabhumi Taipei City Taiwan Taoyuan Intl
$1,137EVA Air
Wed, Sep 2 - Sun, Sep 13

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Etihad Airways flights from Washington, D.C. to Ko Samui

Our best Etihad Airways deals on Washington, D.C. to Ko Samui flight tickets
Etihad Airways
Nov 22
IAD2:35 pmWashington, D.C. Dulles Intl
30h 45m
2 stops
USM9:20 amKo Samui
Dec 2
USM12:40 pmKo Samui
32h 25m
2 stops
IAD9:05 amWashington, D.C. Dulles Intl
$1,215
Etihad Airways
Nov 22
IAD2:35 pmWashington, D.C. Dulles Intl
30h 45m
2 stops
USM9:20 amKo Samui
Dec 1
USM9:30 pmKo Samui
47h 35m
2 stops
IAD9:05 amWashington, D.C. Dulles Intl
$1,243
Etihad Airways
Nov 24
IAD2:35 pmWashington, D.C. Dulles Intl
33h 20m
2 stops
USM11:55 amKo Samui
Dec 1
USM6:15 pmKo Samui
50h 50m
2 stops
IAD9:05 amWashington, D.C. Dulles Intl
$1,266

Lufthansa flights from Washington, D.C. to Ko Samui

Our best Lufthansa deals on Washington, D.C. to Ko Samui flight tickets
Lufthansa
Nov 22
IAD10:55 pmWashington, D.C. Dulles Intl
34h 10m
2 stops
USM9:05 pmKo Samui
Nov 30
USM4:25 pmKo Samui
39h 40m
2 stops
IAD8:05 pmWashington, D.C. Dulles Intl
$1,269
Lufthansa
Aug 15
IAD3:25 pmWashington, D.C. Dulles Intl
42h 45m
2 stops
USM9:10 pmKo Samui
Aug 23
USM1:30 pmKo Samui
36h 35m
2 stops
IAD3:05 pmWashington, D.C. Dulles Intl
$2,556
Lufthansa
Sep 6
IAD10:20 pmWashington, D.C. Dulles Intl
31h 30m
2 stops
USM4:50 pmKo Samui
Sep 15
USM4:25 pmKo Samui
32h 10m
2 stops
IAD1:35 pmWashington, D.C. Dulles Intl
$6,040

momondo Fare Finder

 
Customize your flight search to find flights from Washington, D.C. to Ko Samui 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 7, 2026.
Use the filters below to find and compare flights from Washington, D.C. to Ko Samui that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Mon 10/5

3:10 pm-10:30 am

2 stops32h 20m

Ko Samui

Thu 10/15

5:25 pm-9:45 am

2 stops27h 20m

$1,057
Quickest round-trip

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Thu 9/3

3:10 pm-7:30 am

2 stops29h 20m

Ko Samui

Tue 9/15

5:35 pm-9:45 am

2 stops27h 10m

$1,067

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Fri 9/4

3:10 pm-9:20 am

2 stops31h 10m

Ko Samui

Tue 9/15

5:50 pm-9:45 am

2 stops26h 55m

$1,067

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Thu 9/17

3:10 pm-8:15 am

2 stops30h 05m

Ko Samui

Thu 9/24

11:25 am-9:45 am

2 stops33h 20m

$1,073

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Fri 9/4

3:10 pm-7:10 am

2 stops29h 00m

Ko Samui

Mon 9/14

2:30 pm-9:45 am

2 stops30h 15m

$1,073

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Wed 9/16

3:10 pm-8:25 am

2 stops30h 15m

Ko Samui

Wed 9/23

5:50 pm-9:45 am

2 stops26h 55m

$1,073

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Wed 9/16

3:10 pm-8:25 am

2 stops30h 15m

Ko Samui

Wed 9/23

5:50 pm-9:45 am

2 stops26h 55m

$1,074

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Mon 10/26

3:35 pm-10:40 am

2 stops32h 05m

Ko Samui

Mon 11/2

4:30 pm-9:05 am

2 stops28h 35m

$1,080

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Sun 9/20

1:15 pm-7:10 am

2 stops30h 55m

Ko Samui

Sun 9/27

5:00 pm-11:05 am

3 stops53h 05m

$1,134

Washington, D.C.Ko Samui

IAD Washington, D.C. Dulles Intl - USM Ko Samui

IADUSM

Washington, D.C. Dulles Intl

Wed 9/2

1:15 am-3:25 pm

2 stops27h 10m

Ko Samui

Sun 9/13

6:25 pm-10:00 pm

2 stops38h 35m

$1,137

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Ko Samui from

How to get the cheapest flight ticket from Washington, D.C. to Ko Samui

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest airline that flies from Washington, D.C. to Ko Samui?

EVA Air, Etihad Airways, and Cathay Pacific are the most popular carriers operating from Washington, D.C. to Ko Samui

When to book flights from Washington, D.C. to Ko Samui

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

Cheap Washington, D.C. to Ko Samui (WAS to USM) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Washington, D.C. to Ko Samui

Fastest flight time

26h 40m

Direct flights

None
The fastest flight from Washington, D.C. to Ko Samui takes 26h 40m
There are no direct flights from Washington, D.C. to Ko Samui. There are no popular flight routes from Washington, D.C. to Ko Samui.
Search flight deals

Frequently asked questions about flying from Washington, D.C. to Ko Samui

  • How far is Washington, D.C. to Ko Samui by plane?

    Washington, D.C. and Ko Samui are 9079.2 mi apart from one another. A reasonable flight in good conditions will take 26h 40m.

  • When did momondo last update prices for flights from Washington, D.C. to Ko Samui Airport?

    Prices for flights from Washington, D.C. to Ko Samui Airport are updated daily.

  • How old do you have to be to fly from Washington, D.C. to Ko Samui 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 Washington, D.C. to Ko Samui Airport.

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

    The required travel and health documents for your Ko Samui Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ko Samui Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

  • What is the most popular airline from Washington, D.C. to Ko Samui?

Traveling to a place near Ko Samui?

Book flights to Ko Samui if you plan to visit one of these locations
Ko Pha Ngan
Ko Tao
Khanom

Why use momondo?

Why should I use momondo to find a flight deal from Washington, D.C. to Ko Samui?

It is quick and easy to find Washington, D.C. to Ko Samui flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to Ko Samui that suits you.

Can I find flights from Washington, D.C. to Ko Samui with flexible booking policies on momondo?

All flight searches from Washington, D.C. to Ko Samui on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from Washington, D.C. to Ko Samui?

Once all potential Washington, D.C. to Ko Samui flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

I’m not ready to book a flight from Washington, D.C. to Ko Samui right now. Can momondo alert me if prices change?

Yes. momondo can track prices for Washington, D.C. to Ko Samui flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.

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