We drove into Namibia through the Vioolsdrif border post in January (our honeymoon was a roadtrip through the country).
What you will definitely need is a certified copy of the vehicle's registration certificate -- that's the RC1 certificate; I have doubts whether the certificate that your annual license disc is printed on will be acceptable, and I didn't try it. If you own the vehicle and have lost it, you can go to the traffic department and obtain a replacement. If you don't own the vehicle (e.g. still financed by the bank), you won't have this (the bank will), and you'll need to ask them for both a certified copy and a letter of permission to take the vehicle across the border -- both are required if the vehicle is not in your name, and if you don't have either, expect the South African authorities to turn you back.
We had the ZA sticker, but no-one really bothered checking it (put one on anyway though, as your mileage may vary). The police clearance certificate is only required for temporary importation (i.e. if you're going to be there for 3 months or longer, or are going in on a work visa); was not required for our 2 week trip.
Other than that, you will be required to pay road tax on the Namibian side (for the wife's Nissan Micra, this was N$ 242). This must be paid in cash, but since the rand and Namibian doller are linked 1:1 and the rand is legal tender in Namibia, this shouldn't be a problem. Make absolutely sure that you keep the receipt: if pulled over at a roadblock (we were, twice), you will be required to produce it.
It should go without saying that you will also need a valid driver's license.
Other things to know about:
- Very few petrol stations accept cards (we only found these in Windhoek and Swakopmund); the vast majority are cash only. Make sure you carry cash for refuelling, but if you run out, the petrol garage shops usually have an ATM in them. Both my bank card (Standard Bank) and the wife's (Nedbank) worked in Namibian ATMs just fine.
- As I've already mentioned, the rand is legal tender in Namibia, so you can happily pay for everything in rands -- just expect to receive change in Nam dollars (or even a mixture of the two currencies if you're close to the border). I strongly recommend that you change all your Nam dollars back to rands before you leave the country: there's no charge to do it in Namibia (dual-currency and all that), but SARS will nail you if you try to do it back home. We did our "foreign exchange" at the petrol garages just north of Vioolsdrif before crossing back into RSA.
- Petrol is cheaper there than here
- It took us 30 minutes to clear the border, and the majority of that time was filling out the Namibian immigration form (one pen between two of us!). Carry some pens for this; the Namibians won't provide you with one. They double as departure forms on your way out, so pick some up on your way in and have it pre-filled for when you leave to save time on your way back home.
