If you already have 6 nights devoted to safari, it is only leaving 3 or 4 for Cape Town, which is just barely scratching the surface. The last 2 years I have spent 6 days each year in Cape Town and there is a lot of things I didn't get a chance to do. It is a fantastic city, I wouldn't take any time away from there, or your safari for that matter. Have a great trip.

Detouring to Vic Falls will cost you at least two days, maybe more. With only 10 days in S.A. and a 6-night safari booked, that only leaves you 4 nights for the Cape Town area and any travel time between C.T. and Jo'burg. I'd skip the Falls on this trip, if I were you. Where is your safari? That will also add travel time.

I'm with the others: with 10 days, stick to SA. With six nights on safari and 4 nights Cape Town you have a great combination. You'd only be diluting your SA experience and making it less relaxing by adding Vic Falls, which in mind is a one night proposition. Best to leave Vic Falls for a stop if you happen to ever return and visit Botswana/Zambia or Zimbabwe.

I'm with the others... just not sufficient time. Besides this would be an expensive extension.

While you don't indicate where you're doing safari, you'd still have to fly (first flight out very early) from CPT to JNB, from here a layover till 2/hr flight to VFA + ZIM Visa cost, hotel if overnighting (including transfer to/from airport/hotel) and then flight returning to JNB (assume this if from where flying home); if homebound from CPT then onward to here for that flight.

To view the Falls, you need only a few hours, if that... so unless you have other things to do while here... save VFA for another trip if you happen to find your way to southern African countries.