Sustainability of an occupational sun safety program, Go Sun Smart (GSS), was explored in a randomized trial, testing dissemination strategies at 68 U.S. and Canadian ski areas in 2004-2007. All ski areas received GSS from the National Ski Areas Association through a Basic Dissemination Strategy (BDS) using conference presentations and free materials. Half of the ski areas were randomly assigned to a theory-based Enhanced Dissemination Strategy (EDS) with personal contact supporting GSS use. GSS use was assessed at immediate and long-term follow-up posttests by on-site observation. Use of GSS declined from immediate (M = 6.24) to long-term follow-up (M = 4.72), F(1, 62) = 6.95, p = .01, but EDS ski areas (M = 6.53) continued to use GSS more than BDS ski areas (M = 4.49), F(1, 62) = 5.75, p = .02, regardless of timing of posttest, strategy × observation F(1, 60) = 0.05, p = .83. Despite declines over time, a group of ski areas had sustained high program use and active dissemination methods had sustained positive effects on implementation.