In process industries, the measurement of void fraction is considerably important for sustainable operations. The erroneous calculation of void fraction is inevitably be the cause of many industrial accidents such as loss of coolant accidents in reactor operations, sweet corrosions in sub-sea oil and gas pipelines and an in-efficient process control of chemical plants. Keeping in view the importance of measuring the void fraction, a non-invasive, experimental study was conducted by using Electrical Capacitance Tomography (ECT) technique and differential pressure (�P) technique on a cocurrent vertical gas-liquid flow in a bubble column. A series of experiments were performed by regulating the flow rates of air and deionized water in a co-current bubble column to investigate the flow regime and void fraction. The flow characteristics were physically investigated by using visual instruments. In all the experiments air was used as a gas phase following the superficial velocity range of 0.00218 - 0.03 m/sec and deionised water as a liquid phase using the superficial velocity range of 0.00425 - 0.034 m/sec. The estimation of void fraction in a bubble column via �P method shows the influence of superficial gas velocity on void fraction as a linear function which agrees with the void fraction obtained from ECT measurements. The ECT measurement of void fraction also compared with photographic technique. It has been found from the analysis that the measurements generally follow the increasing trend of void fraction with an increase in superficial gas velocity.