The Panare river mouth in Pattani, Thailand, is crucial for local fishers, providing navigation and a docking area. However, sedimentation frequently blocks the entrance, despite a jetty designed to trap it. This hinders fishing activities and necessitates ongoing dredging. To address this, authorities bypass sand from the east to the west of the river mouth, significantly impacting shoreline dynamics. This study employed the Digital Shoreline Analysis System (DSAS) and satellite imagery (2007–2021) to analyze these changes. Results reveal accretion east of the mouth (0–0.2 km) due to the bypass, but erosion further east (1.0–3.1 km) where sediment redistribution is insufficient. West of the mouth, accretion occurs within 1 km, followed by erosion (1.1–2.6 km) as bypassed sediment fails to reach this zone. This research provides a comprehensive database for future management of the Panare river mouth, emphasizing the need for strategies to mitigate erosion and ensure sustainable navigability for local fishers, whose livelihoods depend on unobstructed access to this vital waterway.