Dyer Island sits just off the coast of Gansbaai, a town in South Africa's Western Cape. The largest island off Gansbaai's coast, Dyer Island sits roughly five miles from shore. It was originally called Ilha de Fera, Portuguese for “Island of Wild Creatures,” which makes sense given that the island is home to hundreds of African penguins.
Another nearby island has thousands of resident Cape fur seals, and the channel between the two islands is known as “Shark Alley” for the high numbers of great white sharks found there. As you might guess, the sharks like feeding on the seals.
Dyer Island is only accessible via boat tours, since it's a bird sanctuary that is not open to the general public. There are frequent tours, however, for whale-watching and shark cage diving. Gansbaai is just over 100 miles from Cape Town.