Anodic stripping voltammetry (ASV) was successfully integrated into an electrochemiluminescence arsenic (III) sensor to enhance its sensitivity. The cathodic reduction step plays a crucial role in anodic stripping voltammetry, making it more sensitive than cyclic voltammetry. In the ASV-ECL technique, the preconcentration step involves applying a potential of –500 mV for 60 s, which potentially reduces the As(III) species to As0 and allows it to spontaneously deposit onto the electrode surface. Simultaneously, a co-reactant of H2O2 is electrochemically reduced to generate hydroxyl radicals (•OH) during the cathodic reduction step, thereby significantly amplifying the ECL response and enhancing detection sensitivity. The analytical measurement of ASV-ECL was successfully performed by the quenching effect of As(III) on luminol-emitted light. The proposed ECL sensor demonstrated excellent performance for As(III) detection with a low detection limit of 0.0152 µM (15.2 nM), high sensitivity of 6.5865 a.u. µM⁻¹ cm–2, and great stability (RSD = 2.49%). High selectivity was achieved by using an optimized pH 10 buffer solution, supporting efficient luminol deprotonation and retaining As(III) in its soluble state, while forcing interfering metal ions to form insoluble metal (hydro)oxides. Therefore, it is essential to perform the precipitation method as a pretreatment step for real seawater samples before quantifying the level of As(III), ensuring that the presence of interfering ions does not significantly affect the measurement accuracy. Successfully detecting the level of As(III) in a seawater sample demonstrates the sensor's practical applicability and confirms its reliability for environmental monitoring. © 2026 Elsevier Ltd.