Mangroves are well-known for their numerous ecosystem services, including sequestering a significant carbon stock, with soils accounting for the largest pool. The soil carbon pool is dependent on the carbon content and bulk density. Our objective was to assess the spatial variability of mangrove soil physical and chemical properties within the Zambezi River Delta and determine whether it may be associated with geomorphic setting. Plots were classified as one of four geomorphic settings: seaward fringe, creek, riverine, and interior. Additionally, we attempted to determine the source(s) of organic matter contributing to the soil carbon pool and any associated spatial variability therein. Many statistically significant differences were shown with depth and setting. However, variability of the measured characteristics was low when compared to other mangrove settings. Mean carbon concentrations ranged from 1.38 to 2.38 % C and mean bulk density values ranged from 0.75 to 1.02 g cm-3. Stable isotopic signatures showed that the organic matter is likely a mix of mangrove and marine sources, with mangrove-derived sources contributing 42-58 %.