Way Kambas National Park (WKNP) in Lampung Province is one of Sumatra’s key lowland conservation areas, providing habitat for flagship mammal species including the sumatran tiger (Panthera tigris sumatrae), sumatran elephant (Elephas maximus sumatranus), and sumatran rhinoceros (Dicerorhinus sumatranus). This study aimed to analyze species diversity, relative abundance, and daily activity patterns of mammals in WKNP using secondary camera-trap data collected from 197 stations between 2007 and 2016. Records were screened to remove non-wildlife captures (humans, park staff, and unidentified images), then analyzed using the Shannon-Wiener diversity index, record-frequency-based relative abundance, and an activity-pattern classification (diurnal, nocturnal, crepuscular, cathemeral) based on capture time. Analysis of 29,711 independent mammal records identified 37 species with a moderate diversity index (H’ = 2.00), dominated by wild boar (Sus scrofa, 37.6%) and barking deer (Muntiacus muntjak, 24.6%), while still encompassing threatened species such as the sumatran tiger, sumatran rhinoceros, malayan tapir, sunda clouded leopard, and sunda pangolin. Activity patterns fell into four categories: diurnal species (wild boar, barking deer, primates, treeshrews), crepuscular species (mouse/spotted mouse-deer, marbled cat), cathemeral species (sumatran tiger, elephant, sambar deer, sun bear, clouded leopard), and nocturnal species (tapir, sumatran rhinoceros, malay civet, and other small carnivores). The cathemeral activity pattern of the sumatran tiger found in this study (53.6% diurnal; 46.4% nocturnal records) is consistent with earlier findings at the same site. These results confirm the importance of WKNP as a diverse, high-conservation-value mammal habitat, and recommend standardizing future camera-trap monitoring effort to improve the accuracy of abundance estimates.