The "Gombessa" expedition, named after a local term for the coelacanth, will run from 5 April to 15 May, exploring locations in the Jesser Canyon, 120m below the waters of Sodwana Bay, where the strange fish is believed to live.
A fossilised skull described last April by Chinese palaeontologists dates the first coelacanths to 375 million years ago.
They were thought to have died out around 65 million years ago until one was caught off South Africa in 1938.
The grey-brown fish can grow up to 2m in length and weigh as much as 91kg.
But almost nothing is known about how it lives - its habitat, food and reproduction.