Japanese companies are actively hiring highly skilled international talents, making their cross-cultural adaptation a critical issue. This study found that highly skilled international talents adapted to their workplace through proactive behaviors such as “learning behaviors” and “relationship-building behaviors.” Furthermore, many talents could be classified under the “integration” category of acculturation. While this finding may indicate that highly skilled international talents are adapting smoothly to Japanese workplaces, it also implies assimilation into Japanese culture. This assimilation may raise concerns for employers as it does not align with their original goal of leveraging diverse talents from overseas.