<p>The tidal flats of the Huanghe (Yellow) River Delta (YRD) are among the fastest-changing shoreline areas in the world. Given their ecological significance and socioeconomic value, tidal flats are critical for biodiversity conservation, coastal protection, and sustainable development. High-precision, continuous monitoring of tidal flat dynamics is therefore essential for effective coastal zone management. However, the irregularity of tide changes poses challenges for regular remote sensing observations. To address these limitations, this study introduces a surface water identification approach through analysis of coastal land-water transitional characteristics. Using high-temporal-resolution surface water distribution data, this study dynamically captures tidal variations throughout the annual cycle, enabling tracking of tidal flat dynamics across interannual timescales. Applying this approach, a long-term mapping of tidal flats in the YRD from 1985 to 2022 has been completed and a detailed change analysis is conducted. The results show a fluctuating trend of “increase-decrease-increase” in the tidal areas over the period, with an overall decline in total area. Except for the north side of the Huanghe River estuary, the outer boundary of the tidal flat migrated landward. At the old Huanghe River estuary, the coastline fluctuates significantly but generally moves landward. The shoreline on the northern side of the Huanghe River estuary remains stable before 1996, but experiences a sharp increase after 1996, rapidly rising after 2006. The southern side showing a trend of expansion toward the sea before 1997 and contraction landward afterward. These results provide a high-resolution account of tidal flat evolution in the YRD, and can offer critical insights for coastal research, ecosystem management, and policy development. The dataset established in this study serves as a foundational resource for guiding the conservation and sustainable utilization of this vulnerable yet vital coastal ecosystem.</p>