The short version
Most Western passports get 90 days visa-free — including the US, UK, EU, Canada, Australia, and New Zealand. Check yours against the official Department of Home Affairs list, not a blog. Your passport needs two blank pages and six months' validity beyond your stay — South Africa stamps in and out, and immigration will turn you back for insufficient pages.
The two blank pages rule
This is the one that actually catches people. A nearly-full passport is a refused entry, full stop. Count your blank pages before you book, not at the desk.
The biometric capture
At immigration you'll be fingerprinted and photographed on entry. It's routine, slightly slow, and non-negotiable. Build an extra twenty minutes into your first arrival.
Yellow fever
Required only if you're arriving from a yellow-fever-endemic country — most travellers aren't. It applies to transit from parts of South America and equatorial Africa, not from Europe or North America direct. Not required from the UK, US, EU, or most of Asia.
Working and overstaying
Overstaying, even by a day, can mean a fine and a ban on return. Visa-free covers tourism and business meetings, not working or living — if you're unsure about your purpose, check before you fly, not at the counter.