Objectives: In this study, we examined complete switching away from cigarettes across various medico-socio-demographic subpopulations of adult smokers who purchased a JUUL Starter Kit (JSK) electronic nicotine delivery system. Methods: We analyzed trajectories of smoking over 12 months in 17,986 adult smokers who purchased a JSK. Populations of special interest were characterized by race/ethnicity, income, diagnoses of potentially smoking-related illness (SRI), depression, and anxiety. Results: Across all 16 subgroups examined, a consistent pattern of trends was observed where complete switching increased, and dual-use decreased over time. Non-Hispanic Asian race/ethnicity, low income, diagnoses of potential SRI, depression, and anxiety were associated with significantly lower switching rates; however, complete switching rates at month 12 were near 50% for all groups, and surpassed the dual-use rates in all subgroups except for those with potential SRI. Conclusions: Substantial rates of complete switching were consistently achieved across all medico-socio-demographic subgroups 12 months following the purchase of the JSK. The potential benefits of switching with JUUL on smokers are likely to be experienced by a wide range of adult smokers.