Flying from South Africa — México
There are no non-stop flights from South Africa to México. The straightest line — although not the cheapest — is to fly South African Airways non-stop from Johannesburg to São Paulo and then connect with Aeroméxico non-stop to México City.
An alternate route through the US is to fly Delta non-stop from Johannesburg to Atlanta. From Atlanta, many airlines connect to numerous destinations in México. (For more information on getting to México from the US, read the article "Flying from the US.")
And via Europe, Air France, British Airways, Iberia, Lufthansa, and South African Airways fly non-stop from Johannesburg and Capetown to European hubs, with non-stop connections available to México City and US hubs.
Even though there doesn't seem to be much variation in prices, the peak travel times from the southern hemisphere to México are the summer months of June and July and the winter months of December and January.
A quick way to figure out carrier, route, and fare options is to check a few of the travel search websites such as www.travelocity.com and www.expedia.com.