The development of hydrokinetic turbines has been motivated by the desire to reduce fossil fuel reliance, energy production costs, and greenhouse gas emissions. Detailed information about fish interactions with hydrokinetic turbines is limited; therefore, this study sought to characterize the interactions between a turbine (RivGen; Ocean Renewable Power Company) and Sockeye Salmon Oncorhynchus nerka from one of the most productive populations in the world—that in the Kvichak River, Alaska. By viewing real-time video imagery, our objectives were to quantify the number of Sockeye Salmon smolts that interacted with the turbine and to assess the behaviors/outcomes of these interactions during the species' smolt out-migration. From May 21 to June 10, 2021, a total of 2,374 Sockeye Salmon smolts passed through the field of view of cameras placed immediately downstream of the hydrokinetic turbine. The majority of these observed events occurred over a short (5-d) time period from late May to early June during periods of darkness (0000–0400 hours). Fish were observed passing through the hydrokinetic turbine in both normal and disoriented manners, with the rotational status/speed of the hydrokinetic turbine appearing to influence passage behavior. Blade strikes on fish were also observed, all of which occurred when the turbine was rotating at high “production” speeds. After temporally and spatially extrapolating the observed fish interactions to account for our subsampling, the results suggest that when monitoring was conducted, the hydrokinetic turbine interacted with approximately 200,000 Sockeye Salmon smolts during this species' smolt out-migration period. This study adds to the sparse knowledge base on fish interactions with emerging riverine hydrokinetic devices and may inform strategies to mitigate the impacts of developing energy projects on socially and culturally important fisheries.