In long-lived species the reproductive population contains many generations, and the genetic structure of that population integrates many year-classes produced under a variety of conditions that affect the mating of adults and dispersal of larvae. Analyzing the genetic structure of both the adult population and individual year-classes provides information on both evolutionary events that shaped the population genetic structure and contemporary events that may have limited or promoted dispersal. As settled juveniles and adults, blue rockfish (Sebastes mystinus) are non-migratory inhabitants of kelp and rocky reef habitats in the eastern Pacific, contain approximately 8 generations of reproductive adults, and possess a pelagic larval and juvenile stage lasting over three months. Given the extended pelagic larval phase of this species, there is a potential for long-distance dispersal. I analyzed the genetic structure of the adult population throughout the range and contrast this to two different juvenile year-classes by using microsatellite markers and mitochondrial DNA sequence data (Control Region). Results of the population genetic analysis of the adults revealed two genetically distinct types and suggest an area of admixture between the two types. Results of the microsatellite analyses also revealed significant genetic structure among juvenile locations in both year-classes that in some cases was spatially and temporally ephemeral. These results suggest that potential dispersal may not translate into realized dispersal in a given year and that dispersal ability of larvae or reproductive potential of the adults may vary annually. Therefore, the genetic structure of individual year-classes within that adult population provides additional information that may help to elucidate the evolutionary relationships among adult locations throughout the species’ range.