Abstract: Conventional FTO-based thin-film photoelectrodes for photoelectrocatalytic water splitting suffer from inherent drawbacks including weak interfacial adhesion between the active layer and the conductive substrate, as well as susceptibility to active layer detachment during prolonged operation, which severely compromise the service lifetime and device reliability of photoelectrodes. To fundamentally address the above bottleneck of interfacial failure, this study proposes an integrated ceramic photoelectrode strategy, aiming to explore a novel photoelectrode architecture with both high structural stability and excellent photoelectrochemical performance by eliminating the “substrate-active layer” binary interface. Commercially available Fe₂O₃ and Cu₂O powders were employed as model materials to fabricate integrated ceramic photoanodes and photocathodes via a pressing–solid-state sintering process under air and argon atmospheres, respectively. The phase structure, morphology, optical absorption, and interfacial charge transfer kinetics of the electrodes were systematically characterized by XRD, SEM, UV-Vis DRS, Mott-Schottky analysis, and EIS. The photoelectrocatalytic activity and stability of the single electrodes were evaluated by LSV, chronoamperometry (J-t), and IPCE measurements under simulated solar illumination (AM 1.5G, 100 mW/cm²). Furthermore, a tandem full cell was assembled by connecting the Fe₂O₃ ceramic photoanode and Cu₂O ceramic photocathode in series to evaluate its unbiased overall water splitting performance. The ceramic electrodes retained the intrinsic crystalline phases of Fe₂O₃ and Cu₂O, forming millimeter-thick dense polycrystalline skeletons without delamination. Compared with thin-film electrodes, the ceramic electrodes exhibited an approximately one order of magnitude higher carrier density and a 4.7- to 8-fold reduction in interfacial charge transfer resistance. The Cu₂O ceramic photocathode achieved a photocurrent density of 287.35 μA/cm² at −0.61 V vs. Ag/AgCl with an IPCE of 17.01%, while the Fe₂O₃ ceramic photoanode achieved an IPCE of 12.25%. After 1000 s of continuous testing, the ceramic electrode retained 64% of its initial photocurrent, substantially outperforming the thin-film electrode (39%). Post-reaction characterization revealed intact surface morphology and no detectable impurity phases within the XRD detection limit for the ceramic electrode, whereas the thin-film electrode exhibited severe active layer detachment. The tandem full cell assembled from the two ceramic electrodes delivered photocurrent densities of −0.32 and 0.37 mA/cm² at the photocathode and photoanode sides, respectively, under unbiased conditions, with ABPE values of 0.01% and 0.04%, demonstrating the feasibility of extending all-ceramic photoelectrodes from single-electrode to device-level applications. This study confirms that the integrated ceramic architecture effectively enhances the structural stability and photoelectrochemical performance of photoelectrodes through a synergistic mechanism involving the elimination of interfacial failure, suppression of electrolyte permeation via high density, and facilitation of charge transport through continuous chemical bond networks. This work provides a new design paradigm and experimental basis for developing highly stable and low-cost integrated photoelectrodes.