Surname Watwithayakhun (Watwithayakhun 
) , in all the world, is a very rare last name. The cognomen Watwithayakhun is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Watwithayakhun | Thailand |
Somchai, Thirapiya, and Tharatchaya