Microplastic contamination in coastal sediments represents a growing environmental concern, particularly in tropical regions where intensive coastal development and diverse anthropogenic activities contribute to plastic accumulation. However, spatially resolved information on microplastic abundance, morphology, and polymer composition remains limited in the coastal environments of Eastern Mindanao, Philippines. This study assessed the spatial distribution and characteristics of sediment-associated microplastics across five coastal locations representing fishing communities, estuarine environments, industrial-port activities, tourism, and aquaculture. Surface sediment samples were processed using density separation and chemical digestion, followed by microscopic characterisation and Fourier-transform infrared spectroscopy (FTIR) for polymer identification. Microplastics were detected at all sampling locations, with concentrations ranging from 76 ± 9 to 187 ± 22 particles/kg dry sediment. The highest concentration was observed in the industrial-port area, whereas the lowest occurred at the less populated tourist beach, indicating spatial heterogeneity in microplastic accumulation across different coastal settings. Fragments and fibers predominated across the sampling locations, suggesting contributions from the fragmentation of larger plastic debris and potentially fiber-releasing activities. FTIR analysis identified polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), with PE and PP collectively accounting for more than 60% of the identified particles. Variations in microplastic abundance, morphology, color, and polymer composition indicated potential relationships with surrounding land-use characteristics, although specific pollution sources could not be conclusively established. The principal contribution of this study is the integrated characterisation of microplastic abundance, particle morphology, and polymer composition across contrasting coastal land-use settings in an understudied tropical island region. The findings establish a preliminary baseline for sediment microplastic contamination in Eastern Mindanao and provide evidence to inform targeted pollution monitoring, source investigations, and coastal waste-management strategies.