If you are going South Africa for vacation, then you should buy a prepaid sim card at arrival. Because roaming charges from T-Mobile, AT&T or Verizon are very expensive in Southern Africa. So you have to pay more euros for incoming and outgoing calls.
Most of the time you have to reserve in South Africa a table in a restaurant or discuss something with the host of the next guest house. Here the telephone costs can then quickly add up. Therefore our recommendation: Buy in South Africa a prepaid Sim card. The advantages we want to listen to you here:
Reasons to buy a SIM card in Southern Africa:
1. Calling and texting is much cheaper
2. The setting up of the prepaid card is very fast and costs about 10 minutes of your time
3. You get your own phone number in South Africa, it is deleted in case of non-use after three months incl. Your Sim card account
4. You receive various goodies such as free minutes, free text messages or free mobile data usage
5. The new sim card costs about 10$ and you have here about 12 free minutes to call
We can recommend the carrier "Vodacom" for South Africa. This provides a very good coverage and very good freebies, after having set up the prepaid card. Have fun in South Africa!