(1) Background: This study aims to describe the primary sources of e-cigarettes among young people and to explore how these sources may differ by individual-level characteristics. (2) Methods: Data were obtained from a cross-sectional, continuous tracking survey of participants. The analytic sample includes current e-cigarette users (aged 15–20 years) surveyed from January to August 2022 (N = 1296). Respondents provided information on e-cigarette source of acquisition, device type, and flavors used, as well as sociodemographic and residential characteristics. Chi-square tests were used to determine differences in source of acquisition by age, gender, race/ethnicity, United States (US) census region, urban-rural classification, flavors used, and device type. (3) Results: Although most current e-cigarette users obtained their devices through a social source (56.9%), a considerable proportion obtained e-cigarettes from a retail source (43.1%). The primary retail sources of e-cigarette acquisition were vape shops (22.0%) and gas station/convenience stores (15.9%). Source of e-cigarette acquisition differed by age, gender, US census region, flavors used, and device type, such that a lower proportion of those who were younger, female, residing in the West, and used vape pens had reported obtaining e-cigarettes via retail sources. (4) Conclusions: Results indicate that a significant proportion of youth report obtaining e-cigarettes from retail sources, despite the federal, state, and local policies that prohibit the sale of any tobacco products to those under the age of 21. Comprehensive retail regulations to help restrict tobacco product access are needed to reduce e-cigarette use among young people.