Hi Thomas!

Your car IU number can be found in your vehicle's log card.

To access your vehicle's log card, simply login to One Motoring website: https://onemotoring.lta.gov.sg/content/onemotoring/home.html with your Singpass, select 'Vehicle Hub', 'Enquire & print vehicle registration details', select the vehicle registration number of the required vehicle!

Find out more here: https://www.motorist.sg/article/524/everything-you-need-to-know-about-your-in-vehicle-unit-iu