Dissolved oxygen is one of the leading indicators of aquatic quality. This study explored a membrane-based bubble generator (MBG) for oxygen dissolution in water. It is achieved by creating negative pressures to suck the air through a thin, porous film and forming bubbles in liquid water. Both airflow and liquid flow rates played essential roles in forming the bubbles. The highest oxygen dissolution energy efficiency of 1.48 kgO2/kWh was achieved under free-flowing air at corresponding air and liquid velocities of 4.87 L/min and 2.46 m/s, respectively. The obtained oxygen dissolution energy efficiencies were comparable with established commercial oxygenators. The results revealed a promising application of porous membranes in MBG as a potential energy-efficient oxygen dissolution technology. © 2022