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Cheap flights from Washington, D.C. to Ko Samui from $1,157

This is the cheapest round-trip 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 9/13. 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 - 7:10 am
IAD
-
USM
29h 00m
2 stops
Multiple Airlines Logo
8:45 am - 9:45 am
USM
-
IAD
36h 00m
2 stops
$1,157Multiple Airlines
Sun, Sep 13 - Sun, Sep 27
Multiple Airlines Logo
3:10 pm - 7:10 am
IAD
-
USM
29h 00m
2 stops
Multiple Airlines Logo
8:45 am - 9:45 am
USM
-
IAD
36h 00m
2 stops
$1,200Multiple Airlines
Sun, Sep 13 - Sun, Sep 27
Qatar Airways Logo
8:05 pm - 10:40 am
IAD
-
USM
27h 35m
2 stops
Qatar Airways Logo
6:15 pm - 3:55 pm
USM
-
IAD
33h 40m
2 stops
$1,410Qatar Airways
Thu, Oct 29 - Mon, Nov 2
Etihad Airways Logo
3:10 pm - 7:10 am
IAD
-
USM
29h 00m
2 stops
Etihad Airways Logo
5:55 pm - 9:45 am
USM
-
IAD
26h 50m
2 stops
$1,454Etihad Airways
Mon, Jul 13 - Mon, Jul 20
Multiple Airlines Logo
9:00 pm - 10:30 am
IAD
-
USM
26h 30m
2 stops
Multiple Airlines Logo
5:55 pm - 3:40 pm
USM
-
IAD
56h 45m
2 stops
$1,662Multiple Airlines
Sun, Aug 16 - Wed, Aug 19
Qatar Airways Logo
9:00 pm - 6:15 pm
IAD
-
USM
58h 15m
2 stops
Qatar Airways Logo
5:25 pm - 3:40 pm
USM
-
IAD
33h 15m
2 stops
$1,949Qatar Airways
Fri, Aug 7 - Sat, Aug 15
Cathay Pacific Logo
11:35 am - 7:40 pm
DCA
-
USM
45h 05m
2 stops
Cathay Pacific Logo
11:55 am - 11:31 pm
USM
-
DCA
46h 36m
2 stops
$2,164Cathay Pacific
Mon, Jul 13 - Mon, Jul 20
Cathay Pacific Logo
6:00 am - 7:40 pm
DCA
-
USM
26h 40m
2 stops
Cathay Pacific Logo
11:55 am - 5:59 pm
USM
-
DCA
41h 04m
2 stops
$2,381Cathay Pacific
Sun, Aug 16 - Wed, Aug 19
British Airways Logo
9:30 pm - 9:10 pm
BWI
-
USM
36h 40m
2 stops
British Airways Logo
1:30 pm - 7:40 pm
USM
-
BWI
41h 10m
2 stops
$2,506British Airways
Thu, Oct 1 - Mon, Oct 5
British Airways Logo
9:30 pm - 9:10 pm
BWI
-
USM
36h 40m
2 stops
British Airways Logo
1:30 pm - 7:40 pm
USM
-
BWI
41h 10m
2 stops
$2,507British Airways
Thu, Oct 1 - Mon, Oct 5

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

Our best Emirates deals on Washington, D.C. to Ko Samui flight tickets
Emirates
Jul 28
IAD10:55 amWashington, D.C. Dulles Intl
47h 15m
2 stops
USM9:10 pmKo Samui
Aug 4
USM2:30 pmKo Samui
53h 10m
2 stops
IAD8:40 amWashington, D.C. Dulles Intl
$4,576
Emirates
Jul 31
IAD10:55 amWashington, D.C. Dulles Intl
47h 15m
2 stops
USM9:10 pmKo Samui
Aug 7
USM2:30 pmKo Samui
53h 10m
2 stops
IAD8:40 amWashington, D.C. Dulles Intl
$5,788
Emirates
Aug 1
IAD10:55 amWashington, D.C. Dulles Intl
47h 15m
2 stops
USM9:10 pmKo Samui
Aug 8
USM5:25 pmKo Samui
50h 15m
2 stops
IAD8:40 amWashington, D.C. Dulles Intl
$5,852

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

Our best Qatar Airways deals on Washington, D.C. to Ko Samui flight tickets
Qatar Airways
Oct 29
IAD8:05 pmWashington, D.C. Dulles Intl
27h 35m
2 stops
USM10:40 amKo Samui
Nov 2
USM6:15 pmKo Samui
33h 40m
2 stops
IAD3:55 pmWashington, D.C. Dulles Intl
$1,410
Qatar Airways
Aug 7
IAD9:00 pmWashington, D.C. Dulles Intl
58h 15m
2 stops
USM6:15 pmKo Samui
Aug 15
USM5:25 pmKo Samui
33h 15m
2 stops
IAD3:40 pmWashington, D.C. Dulles Intl
$1,949
Qatar Airways
Jun 25
IAD11:05 amWashington, D.C. Dulles Intl
36h 25m
2 stops
USM10:30 amKo Samui
Jul 31
USM6:55 pmKo Samui
31h 45m
2 stops
IAD3:40 pmWashington, D.C. Dulles Intl
$2,404

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 June 17, 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 - USM

IADUSM

Washington, D.C. Dulles Intl

Sun 9/13

3:10 pm-7:10 am

2 stops29h 00m

Ko Samui

Sun 9/27

8:45 am-9:45 am

2 stops36h 00m

$1,157

Washington, D.C.Ko Samui

IAD - USM

IADUSM

Washington, D.C. Dulles Intl

Sun 9/13

3:10 pm-7:10 am

2 stops29h 00m

Ko Samui

Sun 9/27

8:45 am-9:45 am

2 stops36h 00m

$1,200

Washington, D.C.Ko Samui

IAD - USM

IADUSM

Washington, D.C. Dulles Intl

Thu 10/29

8:05 pm-10:40 am

2 stops27h 35m

Ko Samui

Mon 11/2

6:15 pm-3:55 pm

2 stops33h 40m

$1,410
Quickest round-trip

Washington, D.C.Ko Samui

IAD - USM

IADUSM

Washington, D.C. Dulles Intl

Mon 7/13

3:10 pm-7:10 am

2 stops29h 00m

Ko Samui

Mon 7/20

5:55 pm-9:45 am

2 stops26h 50m

$1,454

Washington, D.C.Ko Samui

IAD - USM

IADUSM

Washington, D.C. Dulles Intl

Sun 8/16

9:00 pm-10:30 am

2 stops26h 30m

Ko Samui

Wed 8/19

5:55 pm-3:40 pm

2 stops56h 45m

$1,662

Washington, D.C.Ko Samui

IAD - USM

IADUSM

Washington, D.C. Dulles Intl

Fri 8/7

9:00 pm-6:15 pm

2 stops58h 15m

Ko Samui

Sat 8/15

5:25 pm-3:40 pm

2 stops33h 15m

$1,949

Washington, D.C.Ko Samui

DCA - USM

DCAUSM

Washington, D.C. Reagan-National

Mon 7/13

11:35 am-7:40 pm

2 stops45h 05m

Ko Samui

Mon 7/20

11:55 am-11:31 pm

2 stops46h 36m

$2,164

Washington, D.C.Ko Samui

DCA - USM

DCAUSM

Washington, D.C. Reagan-National

Sun 8/16

6:00 am-7:40 pm

2 stops26h 40m

Ko Samui

Wed 8/19

11:55 am-5:59 pm

2 stops41h 04m

$2,381

BaltimoreKo Samui

BWI - USM

BWIUSM

Baltimore/Washington

Thu 10/1

9:30 pm-9:10 pm

2 stops36h 40m

Ko Samui

Mon 10/5

1:30 pm-7:40 pm

2 stops41h 10m

$2,506

BaltimoreKo Samui

BWI - USM

BWIUSM

Baltimore/Washington

Thu 10/1

9:30 pm-9:10 pm

2 stops36h 40m

Ko Samui

Mon 10/5

1:30 pm-7:40 pm

2 stops41h 10m

$2,507

Flights are sorted by cheapest round-trip flights first.

Sorted by cheapest first

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

How often are flights from Washington, D.C. to Ko Samui delayed?

Historically, on average around 21% of flights between Washington, D.C. and Ko Samui have experienced a delay on any given week. The average delay length over the past 12 months has been 131 minutes.

What is the most punctual flight time for Washington, D.C. to Ko Samui flights?

Generally, flights departing in the morning tend to experience fewer delays. Flights in the evening have, in the past, seen delays more frequently in comparison.

What day of the week experiences the fewest flight delays on this route?

Saturday is statistically the day of the week which experiences the fewest number of delays on this flight route. Sunday has historically seen more delays on average compared to the rest of the week.

Which airline has the best punctuality record on Washington, D.C. to Ko Samui flights?

According to our data, Delta have had the least number of delays on this route over the last 12 months; with about 16% of their flights experiencing any sort of delay.

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 30m

Direct flights

None
The fastest flight from Washington, D.C. to Ko Samui takes 26h 30m
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 30m.

  • 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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