Monitoring HIV prevalence using antenatal HIV sentinel surveillance is important for efficient epidemic tracking, programme planning and resource allocation. HIV sentinel surveillance usually employs unlinked anonymous HIV testing which raises ethical, epidemiological and public health challenges in the current era of universal test and treat. The World Health Organization (WHO) recommends that countries should consider using routine prevention of mother-to-child transmission of HIV (PMTCT) data for surveillance. We audited antenatal care clinics to assess the quality of HIV rapid testing practices as the first step to assess whether South Africa is ready to utilize PMTCT programme data for antenatal HIV surveillance. In 2017, we conducted a cross-sectional survey in 360 randomly sampled antenatal care clinics using the adapted WHO Stepwise-Process-for-Improving-the-Quality-of-HIV-Rapid-Testing (SPI-RT) checklist. We calculated median percentage scores within a domain (domain-specific median score), and across all domains (overall median percentage scores). The latter was used to classify sites according to five implementation levels; (from 0:<40% to 4: 90% or higher). Of 346 (96.1%) facilities assessed, an overall median percentage score of 62.1% (inter-quartile range (IQR): 50.8-71.9%) was obtained. The lowest domain-specific median percentage scores were obtained under training/certification (35% IQR: 10.0-50.0%) and external quality assurance (12.5% IQR: 0.0-50.0%), respectively. The majority (89%) of sites had an overall median score at level 2 or below; of these, 37% required improvement in specific areas and 6.4% in all areas. Facilities in districts implementing the HIV Rapid Test Quality Improvement Initiative and supported by the President's Emergency Plan for AIDS Relief (PEPFAR) had significantly higher median overall scores (65.6% IQR: 53.9-74.2%) (P-value from rank sum test: <0.001) compared with non-PEPFAR-supported facilities (56.6% IQR:47.7-66.0%). We found sub-optimal implementation of HIV rapid testing practices. We recommend the expansion of the PEPFAR-funded Rapid Test Continuous Quality Improvement (RTCQI) support to all antenatal care testing sites.