The Thai government enacted a cabinet resolution permitting the registration of irregular migrant workers to attain regular status, access healthcare, and reside legally. This chapter investigates the socio-ecological barriers that prevent MIMWs in Thailand from completing the registration process to achieve regular status. The quantitative survey indicated that a significant proportion (76.4%, n = 304) identified the high cost of registration fees as a primary obstacle in obtaining regular migrant worker status. This was followed by the complexity of the registration process (45%, n = 179) and a lack of knowledge (42.7%, n = 170). Employing a socio-ecological framework, the qualitative findings elucidate the primary challenges impeding registration across intrapersonal-, interpersonal-, institutional-, community-, and policy-level factors. The findings suggest that the registration policy is systematically structured to facilitate temporary or contract-based employment, aligned with labor force demand, while prioritizing national security and economic growth over the protection of migrant workers’ rights.