Siwahla began his career with Ajax Cape Town in 2004. He became the youngest player to score a goal in South African professional football in 2004 at the age of 15 years and 174 days when he scored in an ABSA Cup game against Dynamos.[1] In January 2009, Siwahla claimed that he was assaulted in the dressing room by some of his teammates after a draw with local rivals Santos.[2] The club denied that he was attacked, but admitted that there was an argument about Siwahla's commitment on the field.[2] He was later fined for absconding from training after his accusations and placed on the transfer list.[2]
He joined Bloemfontein Celtic on a season-long loan in July 2009,[3] but returned to Ajax in December 2009 after allegations of ill-discipline.[4][5] Ajax terminated his contract in January 2010[2] and he joined National First Division team FC Cape Town in August 2010 on a two-year contract.[6] Whilst at FC Cape Town, Siwahla attended trials with Turkish Süper Lig club Istanbul BB in 2011 but failed to earn a contract.[7] Despite expressing an interest to join an overseas club at the end of his contract,[2] he joined newly promoted PSL team Chippa United in September 2012 on a one-year deal.[8] He left the club after their relegation at the end of the 2012–13 season.
He joined Mpumalanga Black Aces in July 2013 on a one-year contract[2] but left Aces in October 2013 by mutual consent after he and Mark Mayambela allegedly arrived at training under the influence of alcohol.[9] Both players were asked to undergo alcohol tests at a clinic, but they refused and were suspended pending a disciplinary hearing.[2] The players indicated that they did not want to attend the hearing and the club agreed with their request to be released from their contracts instead.[2]
In 2019, Siwahla returned to Proch Pionki in Poland.[10]