The triathlon takes place on Robben Island for the second year. The swimming is in the harbour and the cycling and running track is around the island, taking in many of the landmarks, including the hard-labour limestone pits and the lighthouse.
There are two races, a shorter one beginning at 07.45 and a longer one at 09.00. Participants are also offered accommodation in one of the ex-prison cells.
Robben Island was used as a leper colony at the end of the 19th century and as a high security jail for opponents of apartheid from 1961 until 1996. Nelson Mandela was imprisoned there from 1964-1982. The prison has since been turned into a museum in memory of the apartheid era.
There is also a Muslim shrine on the island to one of Cape Town's first imams, Sayed Abrurahman Moturu, who was imprisoned on the island and died there in 1754.
The island is listed as an UNESCO World Heritage site.