Border crossings between Botswana and South Africa or Namibia are usually straight-forward and hassle free. You’ll need to have some cash for road and vehicle taxes – a few hundred pula or rands – and your vehicle’s papers must be in order. You’ll need a certified copy of the registration papers and a letter from the rental company confirming you as the driver and granting permission for you to take the vehicle across the border.
The Zambian border at Kazungula involves a pontoon ferry and is a bit more chaotic. Officials will want to see reflective tape on the sides of your vehicle, and may check that you’re carrying portable reflective triangles and a fire extinguisher. The border costs are also higher and payable in kwacha or US dollars. It costs about $70 per vehicle for border fees, including the ferry.
The most difficult borders are into Zimbabwe, but the exact conditions are always changing and hard to predict. There will certainly be road and carbon taxes, and compulsory third-party insurance. All fees are paid in US dollars and the total outlay should be around $60 per vehicle, but could be double that or more. Most European and North American visitors can get a $30 single entry visa at the border, but British passport holders may have problems getting a visa. There’s almost always a police check point just past the border post so be careful of your speed, and make sure all your seatbelts are fastened. They may want to see reflective tape on the sides of your vehicle, country stickers, reflective jackets and triangles, and fire extinguisher.