Many campers consider rainwater and toilets a bare minimum at campgrounds and luckily Australia is full of those. Here are 3 campgrounds we found near Great Australian Bight Marine National Park, SA which have toilets and rainwater. No need to bring a shovel this time (although do bring toilet paper - campgrounds aren't always stocked).
#3 Eucla Caravan Park
1 hour 19 minutes (122.8 km) drive from Great Australian Bight Marine National Park
                            Get directions
              - ✓ Pets Allowed
 - ✓ Toilets
 - ✓ BBQ Areas
 - ✓ Powered sites
 - ✓ Caravans
 - ✓ Camper Trailers
 - ✓ Phone Reception
 - ✓ Cabins Available
 - ✓ Water (Non Drinking)
 - ✓ Laundry
 - ✓ Swimming
 - ✓ Kids play park
 - ✓ Allows fires
 - ✓ Family Parks
 - ✓ Telstra 4G
 
#2 Nullarbor Roadhouse Caravan Park
46 minutes (74.9 km) drive from Great Australian Bight Marine National Park
                            Get directions
              - ✓ Pets Allowed
 - ✓ Toilets
 - ✓ Drinking Water
 - ✓ BBQ Areas
 - ✓ Powered sites
 - ✓ Caravans
 - ✓ Camper Trailers
 - ✓ Phone Reception
 - ✓ Cabins Available
 - ✓ Water (Non Drinking)
 - ✓ Laundry
 - ✓ 4WD Trails
 
#1 Koonalda Homestead Nullarbor National Park
35 minutes (37.4 km) drive from Great Australian Bight Marine National Park
                            Get directions
              - ✓ Toilets
 - ✓ Caravans
 - ✓ Camper Trailers
 - ✓ National Parks
 - ✓ Water (Non Drinking)
 - ✓ Walking Trails
 - ✓ 4WD Trails
 - ✓ Allows fires