An ironman is a long-distance triathlon with the 70.3 mile distance - also known as a "half ironman" - consisting of a 1.2-mile swim, a 56-mile cycle and a 13.1-mile run.

The city of Port Elizabeth sits on Nelson Mandela Bay, which first hosted an event staged by Ironman - a Wanda Sports holding company - in 2004 and since last year has hosted the African Championship.

The venue will now host the pinnacle event in the Ironman calendar, with action taking place on September 1 and 2 in 2018.

"We are delighted to bring the Ironman 70.3 World Championship to Nelson Mandela Bay," said Andrew Messick, chief executive officer of Ironman. 

"Tens of thousands of athletes have enjoyed racing in our events in South Africa over the past 12 years and we are excited to welcome some of the world’s most elite triathletes to the African continent."

The 2016 Championships were held in Mooloolaba in Australia with the 2017 event scheduled for Chattanooga in the United States.

"Nelson Mandela Bay is delighted to have been chosen to host the 2018 Ironman 70.3 World Championship," said Athol Trollip, Nelson Mandela Bay's executive mayor.

"We are proud of our excellent track record in hosting the Ironman African Championship - it’s on the strength of this, our climate, our beautiful beaches and our tourism potential that we are now in a position to host this prestigious international event. 

"We look forward to welcoming the world’s athletes to the Bay."