A Singapore citizen or permanent resident can drive in Singapore only after you obtain a Singapore driving license.
If you are holding a driving license issued outside of Singapore and you hold a Student Pass, Employment Pass, or Dependent Pass then you are allowed to drive in Singapore with a valid foreign driving license for a period of up to 12 months. The start date of these 12 months is the date you entered Singapore for this pass. For e.g., this date would not necessarily be the date your pass or visa was issued. It could be the date you entered Singapore prior to the pass was “issued”. After 12 months of the entry date, holders of the above-mentioned passes must convert to a local Singapore driving license.
New Singapore citizens and permanent residents must convert their foreign driving licenses within three months of obtaining citizenship or permanent resident status.