If you hire a motorhome in Australia, you are authorised and insured to travel to Kangaroo Island. However, be sure to inform the agency on the day of departure and sign a document.
You must stay on tarmac roads.
What if something goes wrong on Kangaroo Island?
You will only be responsible for the cost of towing the vehicle back to the nearest agency (Adelaide) or the cost of submerging the vehicle should it take on water on the ferry or elsewhere on the island.