This article examines the everyday lives of Nicaraguan immigrants in Costa Rica to understand the temporal aspects of illegality produced by immigration law. Two sets of temporary measures highlight the temporality of both law and illegality. First, frequent legal reform, temporary immigration measures, and the bureaucratic labyrinth of immigration administration create a sense of Costa Rican immigration law as temporary. The ongoing temporary character of law and the forms of immigrant illegality it generates create uncertainty about the boundaries between legality and illegality among migrants in Costa Rica. Second, Nicaraguans in Costa Rica respond to the indeterminacy of the law and their economic and social position in relation to it through their own temporary measures. These measures constitute two forms of waiting: first, immigrants feel “locked up” by the shifting legal and administrative complexities of immigration; and second, they create quasi‐legal ways to navigate immigration law during the long process of legalization of their status.