Tonga HAS NO ZIP CODES OR POSTAL CODES. It is used in some Countries like Canada, South Africa, USA etc. but not in Tonga . That shouldn’t stop you from using a postal code, Most people have resorted to using 00000 or 12345. These are numbers they generated by themselves. I know that some of you will be asking what to use when filling a form online or when shopping online. you just have to use any code you like but i will suggest using 00000 Mind you 00000 is not the real postal code but since you really need to input your zip or postal code in a form you just have to use anything.