Small carnivores fulfill important ecological roles in forest ecosystems, yet their diel activity patterns and habitat requirements in subtropical forests remain insufficiently documented. Using 116,800 camera-trap days (2021–2024) at the Chebaling National Nature Reserve, Guangdong Province, China, we characterized the diel activity rhythms and habitat selection of four sympatric small carnivore species: the leopard cat (Prionailurus bengalensis), crab-eating mongoose (Urva urva), spotted linsang (Prionodon pardicolor), and masked palm civet (Paguma larvata). Kernel density estimation revealed distinct diel strategies among the four species. The crab-eating mongoose was strictly diurnal, while the leopard cat, spotted linsang, and masked palm civet were all nocturnal. Temporal overlap was high among nocturnal species (Δ = 0.695–0.899) but low between the diurnal mongoose and each nocturnal species (Δ = 0.074–0.371). Seasonal comparisons showed that all species except the crab-eating mongoose maintained highly consistent activity rhythms between the growing and non-growing seasons. MaxEnt modelling indicated that all four species preferred gently sloping terrain with high vegetation cover (NDVI > 0.43) near water sources. However, they differed in aspect preference, habitat breadth, and sensitivity to anthropogenic disturbance. The leopard cat occupied the largest area of suitable habitat (29.08 km²) and favored shaded slopes; the spotted linsang showed notable avoidance of roads; and the masked palm civet exhibited the broadest ecological tolerance. These results suggest that diel activity divergence between the diurnal and nocturnal guilds, together with species-specific differences in microhabitat selection among the nocturnal species, may contribute to reducing interspecific competition within this assemblage. Our findings provide baseline ecological data for the conservation management of small carnivore communities in subtropical forest ecosystems of southern China.