Since the outbreak of COVID-19, as reported by the WHO in December 2019 and subsequently declared a public health emergency of international concern, a distinct set of risk factors and vulnerabilities faced by migrants are affecting their exposure to the pandemic and its associated outcomes. This study aims to analyze the social determinants of health among migrants and their associated factors and compare the socio-demographic characteristics, patterns of COVID-19, and healthcare attendance and utilization among migrant workers and non-migrants. A descriptive study design was used to analyze COVID-19 morbidity among migrant workers. There were a total of 73,762 migrants living in the province by December 2021, with varied statuses and nationalities. Most of the migrants were from Myanmar, constituting about 80.1%. A total of 24,837 COVID-19 cases in Kanchanaburi province were recorded in 2020–2021. COVID-19 cases among migrant workers accounted for 22.3% during the period under review. Half, 2914 (52.7%) of the migrant female workers were victims of COVID-19 infections. Persons under the age of 18 accounted for about one-fifth of all the COVID-19 cases. Older, over 60 years old, Thais had about twice (10.1%) the COVID-19 cases compared with the older migrants (5.5%). There was a significant increase in healthcare attendance and utilization by non-migrants and migrants during the year under review. Migrants are at high risk of COVID-19 infection. Therefore, public health guidance for the prevention of COVID-19 should prioritize safeguarding the health of migrants by considering their individual characteristics and actions. Enhancing health insurance schemes for migrants, particularly vulnerable migrant groups, is critical for inclusive and expanded healthcare access. Physical, social, and economic environments that impact the health and well-being of migrants should be integral to pandemic prevention, preparedness, response, and recovery.