States adamantly attempt to control borders and document populations. Yet immigration persists, as does irregularity, meaning those who are unauthorized and undocumented. States’ immigration regimes—the laws, policies, and procedures that define foreign residents’ rights—have proliferated visa categories and requirements, making it more difficult for potential candidates to understand eligibility and the application process. Such fragmentation of visa categories raises barriers for individuals to gain and maintain legal status, and for state employees to justly process applications. Using complexity literature and examples from Latin America (Chile, Colombia, and Mexico, 2010–2024) I illustrate how such fragmentation generates unnecessary complexity to governing immigration before, at, and within borders. Instead, governments should offer fewer visa categories with simple and consistent requirements applicable to diverse groups, thereby easing documentation of foreign populations and reducing irregularity.