Comrades marathon runner Vincent O'Neill was one of many to complete the gruelling race in Pietermaritzburg on Sunday, the only difference was that he ran the entire way in an eight kilogram rhino suit.

O'Neill crossed the line in 10 hours 38 minutes, and ran in aid of the UK charity Save the Rhino, which raises funds and awareness to fight rhino poaching.

O'Neill said would be fine, despite feeling a bit tender in places due to the chafing.

"I probably need a week to recover," said O'Neill.

The race was one of the hottest in recent years, and the heavy suit compounded the discomfort for O'Neill.

"It was so hot and I just kept on taking water.

"The start was hardest, as it's all uphill, but [as] I got into the race it flattened out and I was able to pick up the pace a bit."

O'Neill said he was joined by other runners who wanted to help him finish.

"At the beginning of the race I was joined by four runners and they ran with me all the way.

"The group grew to about eight as we went along and they stopped when I stopped, and they ran when I ran. The support was incredible. I was just sorry I couldn't wave to them because I had to hold the head."