Last name Ratanakosin (Ratanakosin, รัตนโกสินธุ์ 
) , in all the world, is a very rare cognomen. The surname Ratanakosin is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| รัตนโกสินธุ์ | Thailand |