You can definitely lose weight with water aerobics. Water aerobics classes have a warm up, stretching and cool down phase, surrounded by an aerobic exercise phase where you work at your target heart rate. You control the intensity by adjusting the size and speed of your movements. The water's buoyancy  removes the stress on your joints and feet to reduce the risk of injury. Your muscles work harder than they do on land because the water provides resistance. And to make it even better, some classes incorporate rhythmic dance movements, and all classes form a social connection that keeps you coming back.