If your conviction is not recorded, then it will not show up in a criminal history check and you do not have to tell anyone you have a criminal history.
However, just like most things, there are exceptions. Certain people can see it, including the Government, Blue Card services, and other employers or providers that ask whether or not you’ve been “found guilty or pleaded guilty to an offence”.
In addition, certain countries may ask whether you’ve been “found guilty of an offence”, so you should check before travelling to determine their specific requirements.
If a conviction is recorded, it will show up in a criminal history check for a period of 5 years (in the Magistrates Court) and 10 years (in the District and Supreme Courts). After that time, it automatically expires, provided you haven’t committed any other offences. If the sentence is longer than 2 and a half years jail, then the conviction lasts forever.