It is becoming increasingly urgent to respond to coastal hazards as the intensity of tropical cyclones exacerbates flood hazards. Over the last few decades, both the number and severity of hazards have significantly increased. Coastal area growth has eroded the protective benefits provided by natural regions such as mangroves and other coastal wetlands. Such habitats can reduce flood damage through coastal protection processes and despite their importance, there is currently no estimate of the impact mangrove forest characteristics have on the rate of flood risk reduction. This study addresses this gap by developing a numerical model for evaluating the coastal hazard risk reduction provided by potential mangroves in coastal areas. Gonu tropical cyclone (2007) is considered in this paper for the assessment over the Port of Sur, Sultanate of Oman. Several synthetic land covers were developed in the study area by modifying Manning’s coefficient. To do this, MIKE 21 model was used to predict flood characteristics and the results are calibrated by observation data. After the implementation of various land cover scenarios into the model, a reduction of up to 49 % in flow velocity and 17.9 % in inundation depth were found. Furthermore, flow velocity and inundation depth both vary with the change in characteristics of mangrove forests. The results give valuable information for the nature-based disaster risk reduction approach.