Some controversy remains regarding the effects of aquatic exercise on body weight and composition. The purpose of this study was to determine the short-term impacts of the WATERinMOTION aquatics exercise program on body weight and composition without nutritional intervention in sedentary older women with overweight/ obesity. The study was developed as a quasi-experimental project (pre/post-study). Forty-four inactive women were volunteers from a convenience sample with a mean age of 71.1±5.7 years (Ukraine, 2019). Participants were allocated randomly into two groups: WATERinMOTION (n=22) or a control group (n=22). Meanwhile, the WATERinMOTION group performed the WATERinMOTION exercise programme with two weekly sessions of 55 minutes each. The control subjects did not participate in any physical exercises. They were asked to perform their routine activities during the study. Both programmes lasted one month. Height, body weight, body mass index (BMI), waist circumference (WC), fat mass (FM), total body water (TBW), and free fat mass (FFM) were the anthropometric variables that were measured pre/post-study. The analysis found statistically significant differences in body weight (-0.7, P=0.004), BMI (-0.3, P=0.002), and FM (-0.6, P=0.03) between the pre and post measurements of the WATERinMOTION group. Moreover, the comparison of groups at post revealed a significant difference in body weight (P˂0.001), BMI (P˂0.001), TBW (P=0.005), FM (P˂0. 001), FFM (P=0.003), and WC (P=0.007). The WATERin- MOTION programme, which is not associated with nutritional monitoring, showed significant benefits for losing weight and the body composition of sedentary older women who are overweight and/or obese.