Namuka Reef is a broad fringing reef flat situated immediately adjacent to the populous and heavily industrialized areas surrounding Suva Harbor, Fiji Islands. Reef flat sediments are mainly very poorly to moderately sorted carbonate gravels and sands with occasional boulders and very little silt, with terrigenous sediments limited to a narrow, nearshore strip. Bulk sediment geochemical analyses show that trace metal concentrations are generally very low across the reef flat and closely similar to pristine reef areas offshore rather than to the nearby contaminated areas within Suva Lagoon. Exceptions occur close to villages, however, where sediments are enriched in Pb, As, and other trace metals, and possibly near wreck sites on the reef where Fe increases locally. These data together with those for major and minor oxides show that there is little or no movement of sediments from the rivers and deeper lagoon onto the carbonate reef flat even though extreme events such as tsunamis or cyclones affect the area. This indicates that the geomorphic separation of reef flats from adjacent contaminated environments is sufficient to prevent the introduction of solid contaminants. Reef flats may thus retain healthy ecosystems and provide resources to the community even though close to heavily contaminated areas.