In 2009, he was called up to represent the Under-16 side at the Grant Khomo Week competition. In 2010 and 2011, he played for their Under-18 side at the Craven Week tournament. After high school in 2012, however, he moved to Potchefstroom, where he got involved in the youth setup of the provincial side, the, as well as playing rugby for Varsity Cup side. He made eleven appearances in the team during the 2012 Under-19 Provincial Championship season, scoring three tries. In 2013, he played four matches in the 2013 Under-21 Provincial Championship, which included a match against in which he scored two tries. In the Varsity Cup competition, he played six matches for the during the 2013 Varsity Cup competition, scoring two tries. He made eight appearances during the 2014 edition of the competition and ran in six tries as the NWU Pukke reached the final.
His first involvement in first team action came during the 2013 Currie Cup First Division season. He made his debut against the, playing off the bench and scoring his first try within ten minutes of appearing. He made two further substitute appearances against the and. His next taste of first class action came during the 2014 Currie Cup qualification tournament. He started in five of their matches during the competition. Prior to the last round of matches, he was the joint-top try scorer in the league, with a brace of tries against the and the and one each against and putting him on a total of six tries. In their last match of the competition against the, Mahuza and teammate Luther Obi, who was also on six tries for the season before the match – scored four tries each to help the Leopards to a 103–15 victory, which also meant that Mahuza and Obi finished the competition as joint-top try scorers, with ten tries apiece.
In February 2015, Mahuza – along with fellow winger Luther Obi – started training with Port Elizabeth-based side the, following a dispute about the validity of their contracts with the. An agreement was reached and Mahuza officially joined the Kings on 27 February. He made his debut for the EP Kings by starting their first match of the 2015 Vodacom Cup season, a 19–27 defeat to defending champions. After just one season at the Kings, Mahuza left prior to the 2016 Super Rugby season.
