In this study, the authors examined the survivability, or persistence over time, of overall science instruction for English learners (ELs) in treatment and control classrooms within a field-based, quasi-experimental grant-funded project in the United States. The project's goal was to increase ELs' science and language achievement through implementation of a language-infused science inquiry model with scripted lessons as teacher scaffolds. The project included observational data on activity structures in treatment and control classrooms. Using survival analysis, the authors analyzed science inquiry instruction survival (i.e., free of lecture-based teaching) and general science instruction time-on-task survival (i.e., free of interruptions) in both groups during the first year of the project (Grade 5). Results indicated a statistically significant difference in science inquiry and time-on-task science instruction persistence in favor of treatment classrooms. Implications for practitioners and possibilities for future research are considered.