Pumas (Puma concolor) are the most widely distributed felid in the Americas, yet their population density, space use, and responses to disturbance remain poorly quantified in Amazonian forests undergoing rapid land-use change. This gap limits evidence-based conservation planning for large carnivores in tropical landscapes where predator–prey dynamics, interspecific competition, and human disturbance may interact. To address this gap, we evaluated puma density, space use, and temporal overlap with prey and jaguars (Panthera onca) in the lowland forests of southeastern Peru using an integrated camera-trap framework. We estimated density with spatially explicit capture–recapture (SECR) models based on individually identified pumas from paired camera-trap grids, modeled puma space use with single-species occupancy models using 263 camera stations and 25,730 trap nights, and quantified diel activity overlap using independent detections of pumas, prey, and jaguars. SECR models estimated puma density at 1.012 individuals/100 km² (SE = 0.440, 95% CI = 0.448–2.286), and detection probability was strongly influenced by trail placement. The spatial scale parameter corresponded to an estimated 95% home-range area of approximately 182.20 km2. Occupancy models indicated that puma space use was best explained by biotic and landscape-structure covariates, whereas measured anthropogenic disturbance covariates received little support. Conditional model-averaged estimates showed positive effects of jaguar index and prey index, while the interaction between terrain ruggedness and jaguar index was negative. Mean predicted puma space-use probability was 0.573 ± 0.069, and mean detection probability was 0.121 ± 0.017. Activity analyses based on 406 puma, 5,532 prey, and 220 jaguar detections revealed high temporal overlap between pumas and prey (Δ4 = 0.888, 95% CI = 0.844–0.922) and between pumas and jaguars (Δ4 = 0.834, 95% CI = 0.782–0.902). These findings suggest that pumas in this Amazonian landscape occur at a conservative SECR-based density consistent with expectations for tropical forest pumas, use prey- and jaguar-active areas, and do not strongly avoid jaguars temporally. However, terrain ruggedness weakened the positive puma–jaguar association, suggesting that fine-scale landscape structure may mediate coexistence. Conservation strategies should prioritize contiguous, prey-rich forests that maintain structural heterogeneity and support intact carnivore assemblages in human-impacted Amazonian landscapes.