While renting a car in South Africa is commonplace, and there are a lot reputable car rental agencies here are a few tips to simplify your life.

Take the “complete cover” insurance, it may be a bit more expensive but it may save you in the long run
Inform your travel agency if there are multiple drivers so that the booking form contains their details.
Each driver will need their latest driver’s license issued by their local authorities to be able to take the vehicle. It is worthwhile noting that the driver’s license must be valid for a further 12 months from the time you drive away with the vehicle.
Each driver will also need an international driver’s license (in English) for purposes of the South African authorities.
You will need a credit card from one of the stated drivers for in-print, this is a normal procedure where the rental agency will reserve an amount for petrol and damages. They will advise you on the amount to fill the car, should you not fill it up before you return it.

Fill up the car before you return it to be refunded your deposit. Keep the receipt as proof. There are petrol stations at or near all major airports. If you have a GPS device loaded with a current map, these will show.
Before you accept the vehicle allocated to you, ensure that all the tools (jack, spanners, etc.) and spare wheel are present. Also be sure to mark on the sheet given to you, any dents, scratches or other things out of place. If there are any problems, inform the agency immediately, do not take the vehicle. Should you take the vehicle without doing these necessary checks, you will be held liable for any missing items, scratches or dents.

Should you go outside South African borders with your rented vehicle, you will require a cross-border permit. The rental agency can give you the permit. Find out which countries are covered by your rental company.
Accidents
In case of an accident these are the things you will need:
NOTE: take photos with your mobile phone where possible (utilise as many angles as you can), then:
- Get the ID and driver’s licence of the other drivers involved.
- Take photographs of the all the drivers involved.
- Get the addresses and telephone numbers of all the drivers involved.
- Take down the number plates and licence discs of all the vehicles involved. The licence disc is on the windscreen (take photos if possible).
- Get the details of any law enforcement officers on site – this would include name, service number, and station. Also, the name of the commanding officer might be helpful.
- You will need to report the accident at the nearest police station and get the case number.
- Inform and send all the above to your car rental agency and insurance.