They will be required to renounce one of their citizenships upon turning 18 years old.
If your child has not yet reached 18 years old when their citizenship is approved, there will reminders made by JPN, When applying for their MyKad at age 12, the child will receive formal reminder regarding their citizenship status. At 18, during the MyKad renewal process, the child will again be reminded of their obligation to renounce any other citizenship. If the child does not apply for their MyKad at age 12 or fails to update it at age 18, a reminder notice will be sent to the address listed in the parents’ IC records.
If your child has already turned 18 at the time of approval, they will need to renounce their other citizenship immediately. JPN will require the renunciation letter before issuing the MyKad.
Once you have received the citizenship certificate, you can proceed to JPN to apply for the IC and wait for updates. The process may include an interview and other steps. You can expect a call from JPN notifying you that the IC has been approved, at which point you will be required to renounce the other citizenship.
To do this, visit the embassy of the relevant country to begin the renunciation process. You will receive a renunciation confirmation letter, which must be submitted to JPN for the MyKad to be issued.