Thandi started her education at Charles Duna Lower Primary & Johnson Marwanqa Higher Primary School in New Brighton, Port Elizabeth. She completed her high school education at St. Matthews College in Keiskammahoek, Eastern Cape and Inanda Seminary in Durban, KwaZulu Natal. Along with her B Juris, B Proc, LLB and LLM Degrees, she further completed a Certificate in Energy Law at Wits University (October 2002) and an Executive Management Programme at the Kellogg’s Business School, North Western University in Chicago, USA. She was awarded an Honorary Doctorate in March 2001 at the Robert Richard Wright Theological Seminary.

On 20 April 2017, she was admitted as an Advocate of the High Court, by the Honourable Judge President Mlambo and the Judge Francis. Thandi was articled to Attorneys Kondile & Somyalo, a firm of attorneys in Port Elizabeth, until 1983. Thereafter, she was an attorney at the Legal Resources Centre where she was responsible for the training and development of candidate attorneys, paralegals and community advice centers. She also conducted litigation against various organs of the apartheid state in such matters as pass laws, the state of emergency legislation, forced removal and unfair dismissals.

Thandi later trained as a mediator and arbitrator, joining the Independent Mediation Service of SA (IMSSA) as its National Director in 1995. In 1997,

Thandi was appointed National Director of the Commission for Conciliation, Mediation and Arbitration (CCMA), with over 1000 full time and part-time staff in nine Provincial offices. After CCMA,

Thandi joined one of the top commercial law firms in the country as a Director. She started the Labour Law Department involved in major labour law litigation and employment law commercial work. She was appointed as a Commissioner for the Small Claims Court in December 2002, by Deputy Minister for Justice and Constitutional Development, MS C. E. Gillwald. She was also appointed to serve as a part time member of the Competition Tribunal between 2003 and 2012. During this period, Thandi was also appointed Adjunct Professor of Law at Cape Town University. Thandi is a Director and shareholder of Peotona Group Holdings. She sits of several boards, and currently chairs the boards of Impala Platinum. Tokiso Dispute Settlement (Pty) Ltd, BP Southern Africa (Pty) Ltd, De Beers Consolidated Mines (Pty) Ltd, Industries SA (Pty) Ltd Non-Executive Director (Chairperson) Lafarge Mining SA (Pty) Ltd.