This study examined differences in mammal occurrence and activity patterns according to trail type using camera trap data collected along legal and illegal trails in Jirisan National Park, South Korea. Camera trap surveys conducted from 2019 to 2023 yielded 1,122 independent detections of mammals. Mammal occurrence was significantly higher on illegal trails than on legal trails. Activity pattern analysis showed high temporal overlap between trail types for most species, indicating similar diel activity rhythms regardless of trail type. In contrast, Prionailurus bengalensis and Meles leucurus showed differences in activity time distributions between trail types. Species composition analysis revealed species-specific differences in spatial use, whereas no clear differences were detected at the community level. These findings suggest that human activity within protected areas can influence the spatial use and behavioral strategies of wild mammals, highlighting the need for management approaches that balance trail use with wildlife conservation.