The deadline dates are as follows: 22 September 2017 for manually submitted returns; 24 November 2017 for returns submitted electronically at a SARS branch or via e-filling; or.
31 January 2018 for returns submitted by provisional taxpayers via e-filling. (remember the deadline of 31.1.2018 is only applicable for Provisional Taxpayers who are 100% up to date with everything)
http://www.sars.gov.za/TaxTypes/PIT/Tax-Season/Pages/default.aspx
http://www.pkf.co.za/news/2017/submit-your-2017-income-tax-return-submityourreturn-avoidpenalties/