An assessment of the coastal erosion problems along selected stretches around the Zanzibar coastline as well as along the mainland coastline of Tanzania, indicated a significant contribution to the problem by human activities. During the study, 56 eroding beaches were examined to assess the extent of anthropogenic activities to the problem. Human-induced erosion was observed at nine sites. By interfering with natural processes, human activities either initiated erosion or enhanced its rate. The activities identified fall into three categories namely, removal of beach material, removal of the protection against wave battering and obstruction of sediment supply. The observed human-induced erosion has occurred as a negative effect resulting from poor understanding of the natural processes. It was found that sand extraction from the beach for road construction was taking place on Zanzibar because many thought that beach sand is more needed for the roads than it is for the stability of the beach itself. Similarly, mangroves are being cleared in front of newly constructed tourist hotels because the developers are mainly concerned with having a clear view to the sea and absence of mangrove leaf litter to improve the hotel site aesthetics. As such, the mitigation measures that are to be considered in such situations are expected not to be complicated. The findings suggest that the possible negative effects of any coastal development should be considered prior to its execution. In some cases coastal managers need only to establish a catalogue of activities that may not be permissible along a given stretch of coastline.