There are two viewing terraces at JNB
, both enclosed with glass. The one at the international terminal has quite a long walk to get to it, has a very restricted view of the apron and runways and can get very crowded sometimes, as the glass front is not very wide. During summer it can also become very uncomfortable and stuffy. However, one good thing about it is that if a 747 is parked directly below it, you look right down into the cockpit. I was there waiting for my brother's flight to come in and I watched the pilots of a SAA 747 going through all their cockpit preparations, wich was absolutely fascinating. I could even see the captain sitting sideways in his seat reading the daily newspaper, after all preparations had been done, of course.
The viewing deck at the domestic terminal is great. Very large glass front with an excellent view of most of the apron and of runway 03L / 21R. Take-offs from 21R will generally rotate more or less in front of the viewing deck, and landings on 03L will also touch down more or less in front of you. Most planes taxiing to the holding point for 03L will also taxi past on the apron, great whenever a 747 comes past. Also no problems with heat in the summer. It can get a bit crowded from time to time but never as bad as at the international side.