Trait mindfulness is often conceptualized to comprise multiple facets such as attention to and acceptance of present-moment experiences. State mindfulness however is mostly conceptualized as unidimensional. As research on trait mindfulness indicates that differentiating aspects of mindfulness deepens our understanding of its associations with well-being, we tested the presence of four facets at both, the trait and the state level: acting with awareness, nonjudgmental acceptance, present-moment attention, and nonreactivity. Via an experience-sampling technology, 70 participants (aged 20–30 years, 50% female) reported their state mindfulness six times a day for several days. In multiple multilevel confirmatory factor analyses, three of the four facets were corroborated at both levels of analysis. The final three-factor model including acting with awareness, nonjudgmental acceptance, and present-moment attention was superior to a one-factor model implying that state mindfulness can be conceptualized as multidimensional. A multidimensional state assessment will likely be informative for future research questions.