The combined effects of decreased fertility and increased longevity have accelerated population aging in various regions of the world. Unlike other countries, Puerto Rico faces unprecedented levels of working-age migration. The full impact of this high migration on Puerto Rican demographics is not yet fully understood. Contextualizing Puerto Rico's aging process at the international level is useful for identifying the role that migration plays in accelerating the aging of its society. Using estimates from the World Population Prospects 2019, we compared the accelerated aging pattern observed in Puerto Rico with the trajectories of six countries with the largest population of people over 65 in the world, Europe and the Caribbean, from 1960 to 2020. Until 2010, the aging process in Puerto Rico was comparable to that of these countries. However, after 2010, the percentage of the population over 65 in Puerto Rico nearly doubled, from 11% to 21%. This marked increase is not observed in any of the countries compared. We conclude that the rapid aging of Puerto Rico, which evolves from a linear to an exponential trend, is due to increasing levels of migration, mainly concentrated in the working-age population.