Diving off thje Cape is stunning as long as the cold water does not put you off. The Cape offers close to 100 sites which are more or less regularily dived plus a lot to explore. Everything from shallow and easy wrecks and reefs between 5 and 20 m to quite challenging deep sites between 30m and 42m.
Highlights off the Cape are definitely the five Smitswinkel Bay Wrecks, The S.A.S. Fleur, the S.A.S. PMB, Partridge Point, Pie Rock, Ramblers, Photographers, Pyramid and Batsata in False Bay.
On the Atlantic side try to get to the North and South Paw, Strawberry Rock, The Steps, Di's Cracks, The Yacht and the S.S. Maori.
Don't like the African Scuba link. Creates the impression there's nothing but Sodwana and shark cage diving.
I agree with the recommendation of ProDive in P.E. Try to do Evans Peak or some sites on the Riy Banks. Bell Buoy is an easy, shallowish close inshore one with lots of Raggies and Stingrays. The wild side is spectacular but probably undiveable in Feb. due to being the wild side.
Mossel Bay is crap according to my experience. Dived Mitch Reef, a pile of rock covered in 357 tons of redbait. DM catching small dark shyshark was poor excuse for charging us money for this dive.
Knysna has brilliant diving offshore but lazy operators leaving you with shore entries on the Paquita (only at slack high) and the tapas jetty (broken bottles and the odd timex watch. A seahorse if you're really lucky.
Plet is supposed to have lekker sites although I did not manage to see them due to crap viz. (Only dived there once)
Tried to do the scuba trail at Storms River Mouth but the op f...ed us around and they did not have tanks for us when we arrived.
Hope you ejyoy diving here in Cape Town and down the coast and see you in the water.
Juergen