South Africa has around 2800 km of coast between Namibia and Mozambique, washed by two very different currents: the cold Benguela flowing north up the west coast and the warm Agulhas running south down the east. That contrast produces some of the richest marine life anywhere.
Southern right whales
Between June and November, southern right whales migrate from the Southern Ocean to calve in the sheltered bays of the Western Cape. Hermanus, 120 km from Cape Town, claims the best land-based whale watching in the world, and the claim is defensible: the animals come within metres of the cliff path, and the town employs a whale crier who blows a kelp horn to announce sightings. Walker Bay, De Hoop and Plettenberg Bay are equally good and quieter. Boat-based watching is licensed and regulated.
African penguins
The only penguin breeding on the African continent has declined by more than 95 percent in a century and is now critically endangered, largely because of commercial fishing competition for sardines and anchovies. Boulders Beach near Simon Town and Stony Point at Betty Bay are the two accessible mainland colonies, both with boardwalks. SANCCOB in Cape Town rehabilitates oiled and abandoned birds and can be visited.
Great white sharks
Gansbaai and False Bay were the world centre of cage diving, based on the seal colonies at Dyer Island and Seal Island. Since around 2017 the great whites have largely left False Bay, apparently displaced by a pair of orcas specialising in shark livers, and sightings elsewhere have become less predictable. Operators now often encounter bronze whaler and copper sharks instead; ask what is actually being seen before booking.
The Sardine Run
Between May and July, billions of sardines move north along the Wild Coast of the Eastern Cape in shoals visible from the air, pursued by common dolphins, gannets, sharks and Bryde whales. It is the largest biomass migration on earth and can be dived from Port St Johns, though it is weather dependent and not guaranteed in any given year.
Durban and the east
Durban has warm subtropical water, a long promenade, the uShaka Marine World aquarium built into a wrecked ship, and the best surf in the country at New Pier. North of it, iSimangaliso Wetland Park protects 220 km of coast, lakes and estuaries with hippos, crocodiles, nesting leatherback and loggerhead turtles between November and March, and some of the best snorkelling at Sodwana Bay.
Safety in the water
Rip currents are the main hazard on all coasts; swim where lifeguards are on duty. KwaZulu-Natal beaches use shark nets and drumlines at the main swimming spots. Water on the Atlantic side of the Cape rarely exceeds 15 degrees even in summer.