This study investigates whether the type of public health insurance affects outpatient healthcare utilization and out-of-pocket expenditure in Thailand before and during the COVID-19 pandemic. The findings suggest that health insurance type primarily affects provider choice rather than the utilization of outpatient care. Moreover, the insignificant interaction effects indicate that the pandemic does not affect the relationship between health insurance type and outpatient utilization. While the type of health insurance is associated with out-of-pocket spending, but the magnitude of the effect is relatively small in both the pre-pandemic and peri-pandemic periods. Overall, the results suggest that Thailand’s universal health coverage system has continued to deliver on its goals of equitable access and financial protection during the COVID-19 pandemic, despite the fragmentation of public health insurance schemes.