Abstract Background South Korea is poised to become Asia’s first mult-iethnic society with over 5% of its population, totaling more than 2.5 million, being immigrants. This demographic shift presents significant public health challenges linked to widespread, and even intensifying, institutional discrimination in healthcare services. Methods This study reviews discriminatory practices across ten essential health security programs, including National Health Insurance (NHI) system, disability assistance, occupational health services, maternal and child care services, national immunization program, health screening program, and assistance for catastrophic medical expenses. Government data and personal narratives were also reviewed to identify the discriminatory elements that can have significant consequences, including increased disease prevalence, higher incidence of occupational injuries, and broader socio-economic instability among migrants. Results Discriminatory elements were found in most programs, with the exception of emergency medical services. These programs commonly provide fewer benefits or impose stricter eligibility criteria for migrants compared to nationals. In particular, the Korean NHI system demands migrants to pay higher premiums and more rigorous maintenance requirements. Conclusions The findings emphasize the need for urgent reforms to equalize health insurance costs, simplify eligibility criteria for migrants, and broaden the scope of benefits to encompass all residency statuses. Implementing these changes will enhance public health infrastructure, improve occupational safety, and foster better integration of the diverse population, ultimately promoting social cohesion and a fairer health system for all. Key messages • A number of discriminatory elements against migrants have been identified in South Korea’s social security policies that can exacerbate health disparities. • Reforms are needed to expand benefits and relax eligibility criteria for migrants in key healthcare policies, including the National Health Insurance system.