This study represents a program evaluation of "Swim for Health": a multiagency partnership in two local authorities in the United Kingdom that sought to increase aquatic activity participation among four target groups. A theory-driven, scientific program evaluation model was used to assess if the program achieved its stated aims (Rossi et al 2003). Chronological records were maintained. Participation figures were collected and triangulated with 20 semistructured interviews with program stakeholders. Barriers to program implementation included a lack of prior needs-analysis of service provision and the goals of the program did not always match those of stakeholders. However, Swim for Health increased participation in three of four target groups. Program developments were also limited by availability of staff able to deliver novel activities other than aqua aerobics. Consequently participants were primarily women. Implications for future programs are discussed.