Seagrasses are recognized as a nature-based solution for mitigating coastal erosion. However, knowledge on coastal community perceptions regarding coastal erosion causes, impacts, potential mitigation, and the protective role of seagrass meadows is limited in Tanzania. Using stratified random sampling, 323 resident fishers from the Kinondoni and Kigamboni coastal municipalities of Dar es Salaam, Tanzania, were selected to participate in a questionnaire survey to understanding their perceptions of coastal erosion impacts and the protective role of seagrass meadows. Further insights were obtained through key informant interviews with village leaders, elders, and BMU leaders, as well as through nominal group technique involving various beach user groups, and non-participant observation. The study found that coastal communities are highly aware of the causes, impacts, and mitigation measures of coastal erosion, with a notable 85.1 % of survey respondents identifying increased wave energy as the main cause. Nominal group technique revealed various categories affected by erosion, including social activities, properties, sacred sites, livelihood stability, and future development opportunities. The key functions of seagrass meadows as perceived by respondents, including enhancing the natural beauty of coastal waters (97.8 %), supporting fisheries (94.4 %), and providing coastal protection (87.0 %), which ranked third. Destructive fishing was identified as the primary cause of seagrass degradation, notably more severe in Kinondoni. Based on the findings, this study recommends regular awareness campaigns on seagrass preservation. Policymakers should integrate seagrass preservation into broader coastal management plans, promote sustainable fishing, and engage communities to ensure the long-term protection of seagrass meadows as nature-based coastal protection solution.