Yes most of the time you get to roll over unused data except for data bonuses. There are grace periods to adhere to as conditions to roll over unused data bundle.
I have a monthly plan that will expire in some few days but still have large volume of data left, will my data roll over if I subscribed to a cheaper monthly plan?
And you are required to register the special SIM (Visitor’s SIM) with your biometrics, return ticket, and international passport from your country before using the SIM.