This exploratory study evaluated the impact of a Spanish second language (L2) domestic immersion (DI) program that was developed expediently at a large university in the United States in response to widespread study abroad (SA) program closures due to COVID-19. Spanish language learners (n = 14) participated in an intensive, six-week summer immersion program for a total of 96 contact hours over the duration of the program. L2 development was evaluated via a conceptual replication of Issa et al. (2020), which recently provided compelling evidence of the benefits of short-term SA programs. L2 gains were measured using an acceptability judgment task, a lexical decision task, and an elicited imitation task. Results showed that DI learners had significant L2 gains in some of the same areas as the SA students, including subject-verb agreement and scores on the elicited imitation task. Implications for creating and maintaining DI programs in the current educational landscape are discussed.