Aliwal Shoal

About 5 km off the sleepy south-coast town of Umkomaas, Aliwal Shoal is not a coral reef but the remains of an ancient coastline: an aeolianite (fossilised sand dune) thought to date to the late Pleistocene, now crusted with hard and soft corals, sponges and sub-tropical fish. It takes its name from the three-masted vessel Aliwal, which narrowly escaped wrecking on the reef in 1849 under Captain James Anderson. Warmed by the briskly flowing Agulhas current and dived mostly between 5 and 25 m, the shoal is widely rated one of South Africa's premier dive sites and is often said to rank among the world's top ten.

The reef's real fame is its sharks. From July to November, ragged-tooth sharks ("raggies") gather in remarkable numbers, with divers regularly reporting 50 to 60 at a time. Aliwal Shoal is also one of relatively few places worldwide offering cage-free, open-water baited shark dives, run by operators working under Department of Environmental Affairs shark-diving permits: oceanic blacktips are encountered year-round and tiger sharks mainly in summer, while Zambezi (bull) sharks, hammerheads and the occasional whale shark also pass through. Two accessible wrecks add to the draw, both in less than 30 m of water: the SS Nebo, which sank in 1884, and the Norwegian bulk carrier MV Produce, lost in 1974.

The site sits within the Aliwal Shoal Marine Protected Area, first proclaimed in June 2004 under the Marine Living Resources Act and then re-declared and greatly enlarged under the National Environmental Management: Protected Areas Act, effective in 2019, to roughly 670 km² between the Lovu (Illovo) and Mzimayi estuaries. Its zoning protects key deep reefs and the historic spawning grounds of over-exploited seabream, alongside ragged-tooth, tiger and blacktip sharks. Umkomaas lies well south of KwaZulu-Natal's limited malaria zone near the Mozambique border, so the area is malaria-free.