Religiosity, defined as a personal and positive relationship with God, is a complex, multidimensional construct. Prayer, as a central element of religiosity, serves as a primary means of communication with the divine. This study aimed to explore the relationship between the subjective importance attributed to prayer and various parameters of religiosity across early, middle and late adulthood. Grounded in Walesa's cognitive-developmental theory of integral development of religiosity, we investigated whether the importance attributed to prayer was a distinct component within the broader construct of religiosity and whether this relationship varied across developmental periods. A total of 566 Roman Catholic adults from Poland participated in the study (Mage = 49.16 years; SDage = 15.72 years), spanning early (25–39 years), middle (40–59 years), and late adulthood (60+ years). Participants completed the Prayer Importance Scale (PIS) and the Structure and Level of Religiosity Test (SLRT). Network analysis was employed to examine the relationships between prayer importance and parameters of religiosity. Additional analyses assessed the stability of these networks and the potential moderating effect of age. The findings suggest that while the importance attributed to prayer is closely linked to overall religiosity, this relationship remains consistent across adulthood. The lack of age-related differences indicates that fundamental aspects of religiosity and prayer importance are established earlier in life and remain stable over time. These results contribute to the understanding of the multifaceted nature of the relationship between religiosity and prayer importance, and underscore the value of network analysis in psychological research.