The effectiveness and safety of a group aquatic aerobic exercise program on cardiorespiratory endurance for children with disabilities was examined using an A-B study design. Sixteen children (11 males, five females) age range 6 to 11 years (mean age 9y 7mo [SD 1y 4mo]) participated in this twice-per-week program lasting 14 weeks. The children's diagnoses included autism spectrum disorder, myelomeningocele, cerebral palsy, or other developmental disability. More than half of the children ambulated independently without aids. Children swam laps and participated in relay races and games with a focus of maintaining a defined target heart rate zone. The strengthening component consisted of exercises using bar bells, aquatic noodles, and water resistance. The following outcomes were measured: half-mile walk/run, isometric muscle strength, timed floor to stand 3-meter test, and motor skills. Complaints of pain or injury were systematically collected. Significant improvements in the half-mile walk/run were observed, but not for secondary outcomes of strength or motor skills. The mean program attendance was 80%, and no injury was reported. Children with disabilities may improve their cardiorespiratory endurance after a group aquatic aerobic exercise program with a high adult:child ratio and specific goals to maintain training heart rates.