Need help booking?
Unpublished phone-only deals available
RML to USM: distance & flight time
Colombo (Colombo Ratmalana Airport) → Ko Samui (Samui Airport)
1,392 mi
2,241 km · 1,210 nm
3h 30m
estimated nonstop flight time
+1.5h
time difference · heading east
See live RML→USM fares Phone-only fares on this route — call free
Flight time details
1,392 miles nonstop takes roughly 3h 30m gate to gate, flying east. Add 45–90 minutes per connection if there's no nonstop service. Remember to factor the 1.5-hour time gain when reading arrival times on your ticket.
The two airports
- RML — Colombo Ratmalana Airport · Colombo, Sri Lanka
- USM — Samui Airport · Ko Samui, Thailand
Distances are great-circle ("as the crow flies") — the same basis airlines use for frequent-flyer miles.
Alternate airports can cut this fare
Flying from or into a nearby airport is the #1 trick our agents use to beat online prices. Call and we'll compare every combination on one call.
Near RML
- CMB · Bandaranaike International Colombo Airport25 mi away
- KCT · Koggala Airport65 mi away
- HRI · Mattala Rajapaksa International Airport93 mi away
- GIU · Sigiriya Air Force Base97 mi away
Near USM
- URT · Surat Thani Airport69 mi away
- NST · Nakhon Si Thammarat Airport70 mi away
- CJM · Chumphon Airport93 mi away
- UNN · Ranong Airport102 mi away
Frequently asked questions
How far is RML from USM?
The flight distance from Colombo (RML) to Ko Samui (USM) is 1,392 miles (2,241 km, 1,210 nautical miles), measured along the great-circle route airlines actually fly.
How long is the flight from RML to USM?
A nonstop flight takes about 3h 30m gate to gate. Actual time varies with winds, routing and season — eastbound transatlantic flights, for example, are usually faster than the return.
Are there nonstop flights from RML to USM?
Nonstop service on RML–USM depends on the season and the day of week. Run the fare search on this page with the nonstop filter applied to see current direct options; when there is no nonstop, a single connection through a carrier hub adds roughly 2–4 hours to the 3h 30m nonstop estimate.
What is the time difference between Colombo and Ko Samui?
Ko Samui is 1.5 hours ahead of Colombo.
What is the cheapest way to fly from RML to USM?
Compare live fares online, then call CheapoTrav — our agents have unpublished consolidator fares on RML–USM that never appear on search engines, with no booking fees.
Why are some RML to USM fares phone-only?
Consolidator contracts let us sell certain RML–USM tickets below the price airlines permit us to publish online, so those fares can only be quoted over the phone. Call the travel desk and an agent will check phone-only inventory for your dates.