During the COVID-19 pandemic, as immigration and asylum processes were delayed or interrupted, migrants and asylum seekers were stranded at Mexico's northern border. In-transit migrants and asylum seekers are an underserved population, and pandemic preparedness has seldom taken their needs into account. In this article we analyze public health policies developed in Mexico in response to the COVID-19 pandemic and describe how these policies have largely overlooked the needs of vulnerable mobile populations. We reviewed eighty publicly available documents issued by federal, state, and municipal authorities in Mexico between January and September 2020. Only seven policy documents explicitly considered in-transit migrants and asylum seekers and their health care needs. In addition, we identified six major gaps in these policies that, if addressed, would promote greater inclusion of persons in mobility in future pandemic response plans, to protect the health of migrant populations.