Herein, we report for the first time the use of ethanol for the switchable underwater wettability on a rough titanium dioxide (TiO2) surface. The rough TiO2 thin films on the titanium surfaces are fabricated by the high speed wire electrical discharge machining (HS-WEDM) processes, and the resultant surfaces show the switch between underwater superhydrophobicity and oleophobicity via ethanol immersion and dark storage. The underlying mechanism of the switch is depicted, and the result shows that during the ethanol immersion and dark storage, the change of hydroxyl groups leads to the switch. Considering that the use of ethanol is time-saving and low-cost, we anticipate that the use of ethanol will open up a new way of surface wettability change. (C) 2016 Elsevier B.V. All rights reserved.