Aquatic therapy is the use of the properties of water for the therapeutic benefit of people of all ages and abilities. This article illustrates how people with disabilities may maximize the benefits of activities in water, including individual and group work and swimming. The overall aim is to encourage family activity and social interaction. The article discusses the Halliwick Concept developed by James McMillan in the late 1940s at Halliwick, a school for girls with disabilities in London, UK. This concept places strong emphasis on ability rather than disability and on the application of the effects of water on the human body. The concept is based on the application of the 10-Point Program, including (1) mental adjustment; (2) disengagement; (3) transversal rotational control; (4) sagittal rotational control; (5) longitudinal rotational control; (6) combined rotational control; (7) upthrust; (8) balance in stillness; (9) turbulent gliding; and (10) simple progression and basic swimming stroke. Throughout the application of the Halliwick Concept, attention is paid to the effects of the physical properties of water. The properties of particular importance are (1) density; (2) buoyancy; (3) hydrostatic pressure; and (4) turbulence and streamlining. The benefits of aquatics therapy include increased function of the cardiovascular, respiratory, renal, and immune systems; greater mobility; increased muscle strength, stretching, and pain relief; and improved gait.