Access to comprehensive maternity protection could contribute to improved breastfeeding practices for working women. Domestic workers are a vulnerable group. This study aimed to explore perceptions of and accessibility to maternity protection among domestic workers in the Western Cape, South Africa, and potential implications of maternity protection access for breastfeeding practices. This was a mixed-method cross-sectional study including a quantitative online survey with 4635 South African domestic workers and 13 individual in-depth interviews with domestic workers. Results from the online survey showed that domestic workers had inconsistent knowledge of maternity-protection entitlements. Data from individual in-depth interviews showed that most participants struggled to access all components of comprehensive maternity protection, with some entitlements being inconsistently and informally available. Most domestic workers were unfamiliar with the concept of breaks to breastfeed or express milk. Participants provided suggestions for improving domestic workers’ access to maternity protection. We conclude that improved access to all components of maternity protection would result in improved quality of care for women during pregnancy, around the time of childbirth and on return to work, and for their newborns, especially if an enabling environment for breastfeeding were created. Universal comprehensive maternity protection could contribute to improved care for all working women and their children.