American Indian and Alaska Native (AI/AN) birthing people are twice as likely as White birthing people to experience maternal morbidity and mortality. AI/AN people, especially rural residents, face pervasive barriers to perinatal care. Access to health insurance (including Medicaid) and the Indian Health Service (IHS) may mitigate barriers. We used 2016-20 data from the Pregnancy Risk Assessment Monitoring System to examine associations between health insurance and IHS access (before, during, and after pregnancy) and perinatal care use and quality (receiving 75 percent or more of recommended care) among AI/AN people. Most respondents reported Medicaid access and one-quarter reported IHS access during the perinatal period. Among AI/AN people who were uninsured before or during pregnancy, IHS access was associated with 16- and 7-percentage-point higher care use, respectively. Among AI/AN people who attended prenatal or postpartum visits, those with IHS access more often received high-quality care. Overall, those with IHS access had greater utilization and higher quality than those without. Policy efforts to address maternal health inequities for AI/AN people should honor federal trust responsibilities to Tribal nations via sufficient investment in Medicaid, the IHS, and other programs to support high-quality perinatal care.