This article investigates how cross-border mobility in the European shipbuilding industry affected the employment security of workers on standard and non-standard contracts in sending and receiving countries during the COVID-19 pandemic. It draws on qualitative findings from Germany, Italy, Norway, Poland and Romania, where shipbuilding production is integrated into transnational networks, leading to high cross-border mobility. Despite restrictions and a reduction of shipbuilding activities, the east-west labour mobility continued during the pandemic contributing to employment security in the east and addressing labour shortages in the west. The findings show that the type of employment contract, national employment protections and workers’ mobility status (e.g. posted or self-initiated) influence workers’ vulnerability. Specifically, the mobile workers with the most secure employment were also better protected by government measures than those in less secure employment during the pandemic, resulting in hierarchised groups of cross-border labour. Workers engaging in circular migration across Europe were the least protected.