In this opinion article, the author argues that highly skilled migrants in Japan face many challenges and are ineffectively used due to the existence of interior frontiers. Although interior frontiers are more subtle than the external boundaries these migrants have had to cross to enter the country, they have tremendous power over their everyday lives. Ethnocentric attitudes, influenced by Nihonjinron, have contributed to the existence of these frontiers. They emphasise homogeneity instead of flexibility and accommodation, and exist in the workplace. Employers want a homogeneous workplace and highly skilled migrants face strong pressures to assimilate. There is also an insistence on Japanese human resource practices such as seniority-based pay and promotion. An interior frontier also exists in the hiring process, and migrants are less likely to progress beyond the first round of interviews. With Japan’s rapidly aging and declining population and acute labour shortages, there is urgency in addressing these frontiers.