Natural rubber (NR) is often compounded with inorganic fillers such as clay to broaden its applications, reduce the production cost, and also to impart good mechanical properties. In this study, the effect of local clay on physical and mechanical properties of Cambodian clay-filled natural rubber latex foams was investigated. The natural rubber latex foam was produced via the Dunlop method through the conventional vulcanization system with sulfur as the crosslinking agent. The clay loading was varied at 5, 10, 15, and 20 parts per hundred rubber (phr). The preliminary tests of raw natural rubber latex for pH, alkalinity, total solids content (TSC), dry rubber content (DRC), and the volatile fatty acid number (VFA no.) were carried out according to ASTM standard with all the results comply with the accepted value according to the standard. Clay was characterized for mineral compositions using X-ray fluorescence. The particle size distribution analysis showed that clay has diameter ranging from 0.262 to 19 micrometers, suggesting a classification of semi-reinforcing filler. The results of the physical properties showed a considerable decrease in porosity and swelling while the bulk density, true density, compression set, and hardness were significantly increased. Tensile strength exhibited significant increase at high clay loading similar to the elongation at break, whereas tear strength showed significant improvement at the maximum of 15 phr and start to decrease at 20 phr loading. Thermal aging also demonstrated a significant deteriorating effect on the latex foam due to chain scissions, which reduces mechanical strengths but increases in the hardness value. The results, therefore, validate that clay filler incorporation with NR latex provides some reinforcement on the properties of NR latex foam mostly at high clay loading.