Address-change deadline and PIN verification
IC holders, including those living overseas, report a move within 28 days. The service is free. Apply for yourself or yourself plus up to four others; sub-applicants consent within five days. ICA mails a PIN to the new address for verification, then an address sticker for the IC. If a new address is included in an IC replacement/re-registration, the IC application proceeds after PIN verification and the new card carries the address. Citizen children/PR children without ICs do not need this update.
Official ICA source
Written independently from ICA’s English original. The linked source supplies the complete document and subsequent updates.