I see from your bio you have an older car. I believe back then the lower trim cars had dummy spares so the attachment point was still on the upper models without a spare. I’m guessing that attachment point isn’t on the 5th gen car since none have spare tires.
If you'd head over to the Maintenance sub-forum, you'll find a long thread about how to install a spare tire as factory as you want it. A spare is an option in Japan, and standard equipment in Mexico. Any Prius HEV(FWD or AWD) can add a spare. Prius PHEV cannot. I've had mine for well over two years. You can have a complete conversion for around $600-$700. Or you can do a bare minimum install for around $100. Or anything in between. All depends on how much money you want to spend and how polished you want the finished product to be. Parts list is available in the other thread. Easiest conversion is FWD XLE or LTD. AWD XLE and LTD is just a tiny bit harder(1 additional part + 3 nuts to hold it on). FWD LE is more involved. AWD LE just a tiny bit worse.
