This study provides evidence of the relationships between the cellular and subcellular conditions of the terrestrial isopod Armadillidium vulgare hepatopancreatic cells and the degree of ecological disturbance in several Italian sites. Armadillidium vulgare, a commonly used bioindicator, enables the assessment of environmental contamination, due to its capacity to bioaccumulate pollutants, particularly heavy metals. Data from the present study obtained by histological and cytological analyses of hepatopancreatic cells, highlight the novelty to derive from samples collected from several Italian regions and to detect cellular damage, alterations in cellular functions, and bioaccumulation of heavy metals. These cellular function parameters mainly detected by Flow Cytometry (FC) are connected to environmental-pollutant stressors and can be appropriately selected to provide insights for ex vivo monitoring applications. Samples from stressed/perturbed by human activities areas show high frequencies of dead cells and evidence ROS-induced damages. In contrast, samples from control sites exhibit relatively undamaged cells and minimal oxidative stress. This study also documents the accumulation of heavy metals, particularly, cadmium and lead suggesting it was impaired in isopods from contaminated areas. This study emphasises the significance of biomarkers for ecosystem health monitoring in the context of anthropogenic activities. It also contributes to a deeper understanding of the sublethal impacts of pollution on terrestrial isopods and their potential role in ecological risk assessment.