Cognomen Thamasan (Thamasan 
) , around the world, is a very rare surname. The cognomen Thamasan is habitual in Thailand, where it is a very rare surname, and India, where it is an extremely rare surname. More prevalently, Thamasan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Thamasan | India, Thailand |