Despite the extensive dissemination of mindfulness-based interventions, debates persist about the very definition of mindfulness. For decades, the ontological discourse on mindfulness has mainly been confined to the development of operational definitions. To date, the dominant paradigm is the five-facet approach that suggests that mindfulness includes five facets (i.e., Observing, Describing, Nonjudging, Nonreactivity, and Acting with Awareness). However, uncertainty still abounds regarding the potential interplay between the facets. In this preregistered study, we investigated the five-facet approach via network analysis in an unselected sample (N=1,704). To do so, we used two distinct computational network approaches: a graphical Gaussian model (GGM) and a directed acyclic graph (DAG). Each model estimates edges (i.e., the relations between the facets) and the importance of nodes (i.e., the facets) in different ways. Our results indicate that the five facets can be conceptualized as a single, coherent network system of interacting elements. Moreover, both GGM and DAG pointed to the acting with awareness facet as playing an especially potent role in the network system. Altogether, our findings offer viable data-driven heuristics for the field's larger quest to ascertain the foundations of mindfulness.