Roaming is only available on the $28 /mo Base Plan.
You will need to provide either your NRIC or your date of birth to increase your Data Roaming Cap to $300 or $600. Good news: if you want to decrease your Data Roaming Cap, no authentication step is required!
For $600 limit, we will require manual processing. Upon selecting the $600 option, an email dialog will pop up with an auto-filled template to request for the increase in Data Roaming Cap.