Need help booking?
Unpublished phone-only deals available
ONT to USM: distance & flight time
Ontario (Ontario International Airport) → Ko Samui (Samui Airport)
8,542 mi
13,747 km · 7,423 nm
17h 13m
estimated nonstop flight time
+14h
time difference · heading northwest
See live ONT→USM fares Phone-only fares on this route — call free
Flight time details
8,542 miles nonstop takes roughly 17h 13m gate to gate, flying northwest. Add 45–90 minutes per connection if there's no nonstop service. Remember to factor the 14-hour time gain when reading arrival times on your ticket.
The two airports
- ONT — Ontario International Airport · Ontario, United States
- 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 ONT
- CCB · Cable Airport6 mi away
- CNO · Chino Airport6 mi away
- LAX · Los Angeles International Airport47 mi away
- RAL · Riverside Municipal Airport11 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 ONT from USM?
The flight distance from Ontario (ONT) to Ko Samui (USM) is 8,542 miles (13,747 km, 7,423 nautical miles), measured along the great-circle route airlines actually fly.
How long is the flight from ONT to USM?
A nonstop flight takes about 17h 13m gate to gate. Actual time varies with winds, routing and season — eastbound transatlantic flights, for example, are usually faster than the return.
What is the time difference between Ontario and Ko Samui?
Ko Samui is 14 hours ahead of Ontario.
What is the cheapest way to fly from ONT to USM?
Compare live fares online, then call CheapoTrav — our agents have unpublished consolidator fares on ONT–USM that never appear on search engines, with no booking fees.