The South Atlantic/Pacific routes to Africa are EXTREMELY expensive because of lack of competition though sometimes you can get deals:
Southern hemisphere flights:
South Atlantic flights:
MH 744 2x weekly EZE-CPT (continuation of EZE-CPT-KUL, the point of this flight it between South America and SE-Asia, the South Africa stop is just gravy and for CARGO.)
*A: SA 346/343/342 11x weekly GRU-JNB
*A: SA 343/342 3x weekly EZE-JNB
TAAG Angola (newly delivered 77W and 77E's): LAD-GRU 4x, LAD-GIG 3x (they fly this route due to European colonial history, Luanda speaks Portuguese and obviously the much more developed Brasil in South America does too!).
South Pacific flights:
QF 744 7x weekly (daily) SYD-JNB
*A: SA 6x/sometimes 7x/daily PER-JNB (343, 346, 342)
*A: SQ 7x weekly (daily, 772) SIN-JNB
MH 2x weekly 744 (as said above on the South Atlantic part): KUL-CPT
MH 3x weekly 772 KUL-JNB
*A: TG 4x weekly 772 BKK-JNB
*A: SA 3x weekly 343/342 BOM-JNB (code-shared with AI)
*A: 9W (Jet Airways India) 332 3-4x weekly BOM-JNB
The obvious EK 2x dailies to both JNB, CPT and somewhere else from their superhub in DXB (Dubai) and similar with QR (Qatar, DOH-Doha) and EY (Etihad, Abu Dhabi).
If you don't want to take a traditional European/SE Atlantic routing.
If you WANT a really cool route that is growing in ....-load of traffic is between Oceania (Australia, New Zealand) & South America (with connecting traffic from Asia):
LAN: SCL-AKL-SYD 6x soon daily
AR: EZE-AKL-SYD 3x soon when they get more planes more capacity
QF: EZE-SYD 3x soon when they get more planes more capacity