Coastal protection in the Mekong Delta is of paramount importance. The low-lying coastal area has always been vulnerable to flooding by extreme events, but the coastal erosion and consequent land losses have increased to alarming magnitude in the most recent years. This MSc thesis aims to pro- vide insight in the optimal protection strategy for each situation, through investigating the wave load and overtopping of sea dikes, as function of the location of the dike in the cross-section, for different foreshore geometries. The Mekong Delta coast can be classified into three categories, based on the erosion rate: a stable coastline, an accreting coastline and an eroding coastline. For each category, several coastal protec- tion scenarios have been developed. In case of a stable coastline, a simple coastal protection strategy consisting of a sea dike in combination with its foreshore will be most appropriate. The same strategy can be applied to an accreting shoreline, however optimising details may increase the benefits. In the last category, the foreshore erodes. The first strategy is to accept the erosion, and simply place the dike more inland, this is called managed retreat. The second strategy uses the mangrove forest on the foreshore to slow down the erosion. The third strategy stops the erosion by nourishing the foreshore, restoring the sediment balance, and the fourth strategy fights the erosion by constructing a structure that can withstand the erosion and extreme wave loads. In order to be able to numerically model each scenario, boundary conditions are required. Since the Mekong Delta is an extremely varied region, one set of boundary conditions cannot represent the entire Delta, therefore a range of boundary conditions has been set up. Three bathymetric profiles and four vegetation settings have been defined. Further, as the Dutch and Vietnamese approach with respect to the choice of lifetime and return period differs significantly, also 12 combinations of return period and lifetime will be modelled. The numerical models used for this project are SWAN and SWASH. SWAN will translate the offshore boundary conditions into nearshore conditions, and SWASH will use these conditions as input in order to calculate the wave transformation up to the shoreline. During the project, it was discovered that wave transformation on these extremely gentle slopes (in the order of 1:1000) has never been researched, and in combination with the total lack of measurements, the numerical models could not be validated. However, by comparing the model results to theory, and analysing each single source term in the en- ergy balance, some improvements have been made to the model. Thus, sufficient confidence in the model was built up to model the design storm conditions in the Mekong Delta for each scenario. For each situation, all scenarios have been evaluated with a cost-benefit analysis in order to determine the optimal strategy. When the coastline is stable, the cost-benefit analysis showed that there is a direct reduction in net costs as the dike is placed further inland. Further, the additional costs for designing a dike with a longer lifetime or a dike that can withstand a longer return period, are significantly smaller than both the additional benefits and the initial costs. Finally, the construction costs can be reduced significantly by allowing a limited amount of overtopping. In case of accretion, the best coastal protection strategy proved to be a dike with a long lifetime, in combination with alternative use of the foreshore, for example for extensive aquaculture. In case of erosion, managed retreat turned out to be the optimal strategy, however in practice there are often limitations imposed on the distance the dike can be retreated. Mangrove reforestation could only be applied in case of erosion that was limited both in duration and in strength. The other two strategies (nourishment and strong structures) appeared to be extremely expensive, and can therefore only be justified in case the value of the hinterland is high, which is not yet the case in the Mekong Delta. How- ever, the Delta is rapidly developing, therefore it is recommended in the case of erosion to design for a short lifetime and re-evaluate the situation in the near future.