License plates in Ontario are property of and travel with the driver not vehicle. So, what do you do with your plates when you sell your car? Since plates are linked to your name and are not transferable to another individual. You will need to remove them from the vehicle before selling it.
There is no need to return your plates to ministry of transportation and you can keep them yourself. If need arises in the future those plates can be transferred to a new vehicle you might purchase and since plates are not refundable, you pay for them and they are yours to keep.
However, plate sticker is refundable and yearly fee is not that cheap you might consider getting a refund for unused period. Just go to a Ministry of Transportation location and present them your plate ownership and you will get a refund for your unused part of the sticker.
Physical plates are not needed to refund a sticker, just the plate ownership. Plate part is the left portion of ownership; part on the right will be used to sell your vehicle and will be filled up with buyer and seller information.
When you sell your car, one thing you do not want to do is forgetting to remove plates off the car. Plates will always be registered under your name even after you sell your car. If someone drives your car with your plates (even after you already sold it) and get involved in an accident or other shady activities you might be held liable.
You don’t want any headaches coming from the new owner after you already sold the car. What do you with your old plate then?
Your plates can be used again for a new car you might decide to buy or if not need anymore, just throw them away. If you decide to discard them, do not just throw them in the garbage; you never know where they might end up. Make sure you cut your plates in pieces before throwing them away, just to make sure they are not usable anymore.