Japanese migrant policy prioritizes immigration control over migrant rights and welfare, which has clear consequences for migrant healthcare. A literature review and interviews of migrant healthcare advocates revealed that disadvantaged migrant groups have poor health and face barriers in accessing mainstream healthcare, particularly for emergency, HIV/AIDS and maternal and child care. Advocates fashion a provisional safety net from existing policies to connect migrants with essential care, but this approach is of limited effectiveness. Policy solutions and relevant advocate opinion are considered in light of the failure of existing policies to meet uninsured migrants' healthcare needs.