Open Water Swimming Career
Marais participated in the 2009 FINA World Championships in Rome, Italy and the 2011 FINA World Championships in Shanghai, China where he competed in the 5 km races. He also completed the Round The Rocks Swim at Blouberg on 8 May 2011. Marais was part of Team Young Money that won the Relay Race with a prize of $5000.
He is a formidable cold water swimmer and is a former winner of the Youth Day Swim, when the course was from Clifton to Camps Bay. He won the 2.5 km Cadiz Human Rights Day Swim at Camps Bay (on 21 March 2010 and 2012) and the 2014 Metsi Open Water Swim 10 km marathon swim in Jeffreys Bay.