The bubble size, gas holdup, and interfacial area in a swirling contactor were investigated through experiments and simulations. The interfacial area was obtained for liquids and gases with Reynolds numbers Re_l and Re_g, respectively. The contactor was divided into 12 subregions. When Re_g=23.8 and Re_l =20075.4, regions near the side wall and center of the swirl contactor exhibited small bubbles with diameters of 0.33–0.40 and 0.38–0.45 mm, respectively. Re_l was negatively related to bubble size, gas holdup, and interfacial area, whereas Re_g was positively related. The maximum bubble interfacial area among the 12 subregions was 530 m^-1,and for the entire swirling contactor was 196.3 m^-1 with a gas–liquid ratio of 0.022. Euler-Euler simulations using the population balance model accurately predicted this area. Larger areas were obtained at lower Re_l values. Increasing the liquid velocity is not necessary to achieve larger areas, which indicates a contactor with lower energy consumption.