Last name 口 達哉 (口 達哉 
) , globally, is a very rare cognomen. The family name 口 達哉 is habitual in Eastern Asia, particularly China, where it is an extremely rare surname. More prevalently, 口 達哉 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 口 達哉 | China |