Migrant mortality advantage is established in various studies, but there is a lack of evidence on migrant mortality trends in old age. Previous studies have primarily concentrated on all-cause mortality, and few include older age groups. Discussions about the migrant mortality advantage continue due to concerns about data availability and accuracy. Additionally, the mechanisms explaining the migrant mortality advantage remain unclear. This study examines all-cause and cause-specific mortality among older migrant and nonmigrant adults aged 70 and above using Finnish Cause of Death register data (2002-20) and the corresponding risk population. We investigate differences in overall and cause-specific mortality between migrant and Finnish-born population and by geographical region of origin. We calculated direct age-standardized mortality rates and age group-specific death rates followed by Poisson regression to study relative mortality differences. Age at death, sex, income, region of residence, and year of death were controlled for in the regression analysis. We found evidence of migrant mortality advantage across various causes of death, but there was variation by regions of origin groups and sex. Notably, women exhibit the strongest advantage in respiratory and digestive system diseases, while men demonstrated pronounced advantages in external causes and respiratory diseases. Our study challenges the notion of a general diminishing healthy migrant effect in old age. Our findings emphasize the need for nuanced investigations into socioeconomic factors and tailored interventions for older migrants.