In March of 2015, the State of Hawaii stopped covering the vast majority of migrants from countries belonging to the Compact of Free Association (COFA) in the state Medicaid program. As a result COFA migrants were required to obtain private insurance in health insurance exchanges established under the Affordable Care Act. Using statewide administrative hospital discharge data, we show that Medicaid-funded hospitalizations and emergency room visits declined in this population by 69% and 42% after the expiration of Medicaid eligibility. Utilization funded by private insurance did increase but not enough to offset the declines in publicly-funded utilization. This resulted in a net decrease in utilization. In addition, we show that uninsured ER visits increased as a consequence of the expiration of Medicaid benefits. Paradoxically, we also find a substantial increase in Medicaid-funded ER visits by infants after the expiration of benefits which is consistent with a substitution of ER visits for ambulatory care for the very young.