Design and fabrication of micro-/nano-structured photoelectrodes is of significance to utilize the solar energy effectively for hydrogen production from water. In this work, irregular micro-island arrays (MIA) of CdO/CdS composites on fluorine-doped tin oxide (FTO) substrates have been prepared for the first time as photoanodes without using any templates. The MIA-CdO film in the photoanode is obtained by annealing the electrodeposited MIA-Cd film, and it is then converted into the MIA-CdO/CdS film by successive ionic layer adsorption and reaction. The prepared MIA-CdO/CdS composite photoanode possesses these advantages such as large surface area for light absorption and charge production, dense and wide paths for charge separation and transportation, and plentiful channels among the islands for mass transfer between the solution and the CdS surface. The photoanode displays the highest saturation anodic photocurrent density of 6.8 mA cm(-2) ever reported on the CdO/CdS-based photoanodes under visible light illumination of 100 mW cm(-2) in a mixed solution of 0.1 M Na2SO3 + 0.1 M Na2S, which also has a record stable photocurrent density of 4.4 mA cm(-2). (C) 2018 The Electrochemical Society.