With regard to travelling to Kangaroo Island , please click on the link on IMPORTANT INFORMATION near the car photo and then on TRAVEL RESTRICTIONS as many suppliers have differing travel restrictions.
For example :-
ACE RENTALS
"Travel to Kangaroo Island is not allowed"
EAST COAST RENTALS
"The vehicle cannot be taken onto Kangaroo Island, Bruny Island, Fraser Island, Magnetic Island, Groote Eylandt, Gove Peninsula or the Tiwi Islands"
ACCESS
"All international, state and island crossings are disallowed"
ALAMO , FIREFLY, THRIFTY & ENTERPRISE
appear to allow the trip to Kangaroo Island.