This study evaluates the implementation of NATO environmental protection requirements across operational phases using a checklist-based gap analysis. Eight environmental domains within the Czech Armed Forces were assessed by comparing current and target states of compliance. Results indicate overall high to full implementation, with full compliance achieved in waste management, POL handling, HAZMAT and water management. Higher implementation gaps persist in air quality, energy management, and infrastructure planning, reflecting sensitivity to operational constraints. The findings confirm that environmental compliance is phase-dependent and influenced by infrastructure, logistics, and resource availability, highlighting the need for scalable and early integrated environmental measures.