Estuaries are crucial coastal ecosystems that support diverse life, sustain fisheries, and reinforce local economies. However, these environments are increasingly threatened by human activities such as port operations, tourism, fishing, industrial discharges, and waste disposal, leading to heightened pollution levels. A significant concern is the influx of microplastics (MPs), which can adversely affect aquatic life and human health. Despite their importance, MPs are still underexplored within Indian estuarine environments. This study focuses on the Sasihithlu estuary in Karnataka, where the Shambavi and Nandhini rivers meet the Arabian Sea. In May 2024, shoreline sampling was conducted to evaluate the presence and distribution of MPs in this brackish environment influenced by tourism and small-scale industries. The results indicated a mean concentration of 16 ± 0.4 MPs/L in water and 363 ± 137 MPs/kg (dry weight) in sediments. MPs ranging from 500 μm to 100 μm and those between 200 μm and 100 μm were found in water and sediments respectively. Nylon, followed by polyester, was the predominant polymer. Fibers and fragments of transparent and black colors were predominant in the estuary. These findings highlight the need for focused research, sophisticated instruments, and practical strategies to address microplastic pollution in estuarine ecosystems.