Purpose/Hypothesis: Properties of water such as buoyancy, hydrostatic pressure, and fluid resistance when used with aquatic exercises have been shown to have a positive effect on balance and functional mobility. Previous literature has shown these improvements in children with cerebral palsy, spinal muscular atrophy (SMA) type II, and developmental coordination disorder, disorders that could present with similar impairments to children with Down syndrome. Therefore, the purpose of this study was to determine the effect of aquatic therapy on children with Down syndrome. Materials/Methods: Ten children aged 2 to 8 years with a diagnosis of Down syndrome received 1:1 (student therapist:child) therapy sessions, with some children requiring a 2:1 ratio. Prior to aquatic intervention, each child was evaluated using the Pediatric Balance Scale (PBS) and the Water Orientation Test Alyn (WOTA-1). For 8 consecutive weeks, each child received personalized interventions lasting about 45 minutes based upon their needs. After the 8-week aquatic intervention sessions, each child was then reevaluated with both outcome measures. Results: The study began with 10 participants, with 9 completing the 8-week program. Eight of the 9 children made clinically significant improvements in their WOTA-1 scores, and 7 of the 9 children made clinically significant improvements in their PBS score. Conclusions: The use of aquatic physical therapy for children with Down syndrome displayed quantitative improvements in balance, as well as comfort and mobility in the water. Using individualized treatment plans, each child was able to improve in each of the aforementioned areas. Clinical Relevance: This small study demonstrates that children with Down syndrome can gain functional benefits from aquatic therapy similar to previous research in children with hypertonia. As physical therapists, we need to be aware of how aquatic therapy can benefit different subgroups of children so that we can refer and treat as appropriate in order to give children the best functional outcome.