Is a trip by land from Johannesburg to Windhoek realistic ?

As far as I know there are public busses running between Johannesburg & Windhoek. From Windhoek you will be able to travel to Swakopmund.

However, you will need wheels once you have arrived there or be stuck in one place. There is no public transport to the main tourist attractions and you will have to either hire a vehicle or approach one of the tour companies to put together a tour for you. Do get some quotes. One company that have had some good reviews on this branch is Cardboard Box, but there are a number of others.

I personally think that Namibia has become an expensive destination and definitely is not a budget destination.

Is windhoek your final destination?

If not, you'll probably need to take a tour.

Although your route might have the benefit of being a fairly straight line, it might be easier taking the bus/plane/train to Cape Town, and then bus to Windhoek. (Capeliner?)

But, as said, you'll need wheels to get round Namibia.

There is also the odd flight from Johannesburg to Windhoek, and even to Walvis Bay. Direct, nogal.

Well Windhoek is an eventual destination...
Would you recommend gradually going to Windhoek sightseeing on the way there ?

As for the flights, I saw that there are Air Namibia and South African Airlines that have daily flights. Would you know of any other companies ?

If you hire a car in Johannesburg, yes I would recommend sightseeing on the way to Windhoek. Changing the route a bit, here are some places at which you could stop on the indirect route to Windhoek. Some are not directly on route and require detours. Google for each to see if any of them appeal:
1) Witsand (the Roaring Dunes) - in the middle of nowhere, south of the N14, north-east of Groblershoop.
2) Augrabies Falls National Park.
3) Kgalagadi Transfrontier Park
4) Quiver Tree Forest and Giants Playground (near Keetmanshoop)
5) Fish River Canyon (between Ai-Ais and Hobas)
6) Luderitz and Kolmanskop (at the sea - a long detour)
7) Sossusvlei
8) Walvis Bay and Swakopmund
9) Windhoek.

Edited by: RudiK

Haven't been to South Africa or Namibia yet, but I'm going to travel with Intercape from Cape Town to Windhoek. Intercape also drives between Johannesburg and Windhoek and is fairly cheap. http://www.intercape.co.za/index.html

for bus information go at www.computicket.co.za. You can compare price and schedules of the different companies there... However, it's going to be a loooooong trip - and I would think it might not be that cheaper than flying. Kulula also flies from Jo'burg to Windhoek

We did it in july 2008 from Jo'burg to Windhoek with intercape. One night in Upington. Quite long but very cheap.
Few pictures :
http://veroeddy.over-blog.com/article-21941312.html

Enjoy !
Véro