The COVID-19 pandemic has significantly exacerbated the economic, social and political vulnerabilities of internal and international migrants and increased their food insecurity in several cities of the Global South. So far, very little attention has been paid to the dynamics of internal migrants’ food security in urban China since the emergence of the pandemic. Based on the results of an online survey conducted in the cities of Wuhan and Nanjing in early 2020 and a review of secondary materials, this paper identifies the major phases of China’s COVID-19 containment policies and evaluates their effects on the food security of internal migrants through these various phases. Our paper shows that internal migrants in Chinese cities experienced the pandemic-induced food insecurity differently than other urban residents, marked by higher levels of food insecurity and increased food expenditures due to highly restricted mobility and disproportionate income losses. Sudden changes in urban food environments contributed to sharp increases in migrant food insecurity at the beginning of the pandemic. In the later phases, food insecurity was established as a more enduring condition, as the pandemic-induced downturn of the national and local economies led to higher unemployment, and decreased incomes. The limited access of migrants to pandemic support and relief measures also shaped their precarious food security status. Improving the food security of internal migrants in Chinese cities requires structural changes focused on the generation and expansion of economic opportunities for this cohort, combined with improved social protection.