Human actions are changing both terrestrial and aquatic ecosystems, and ultimately causing increased rates of species extinctions. Furthermore, a majority of species’ population sizes and/or geographic ranges are declining worldwide due to anthropogenic stressors. Many of the stressors that impact rocky intertidal ecosystems result from increasing urbanization, recreational activities, and harvest of species at the shore. San Diego’s temperate coastal climate, in particular, attracts large numbers of visitors who conduct recreational activities and harvest species at the ocean water’s edge including the rocky intertidal zone. As a result, following years of planning, several marine areas around San Diego have been protected from harvest as part of a network of Marine Protected Areas (MPAs). This study investigates the level of (1) visitor knowledge about MPAs in San Diego County, (2) visitor activity at select San Diego rocky intertidal study sites, and (3) visitor impacts on the biodiversity of rocky intertidal ecosystems. Specifically, six rocky intertidal study sites will be studied in San Diego, CA. The total number of visitors and their activities will be recorded using an aggregated observation log, while observations of individuals’ activities recorded using individual observation logs. Visitor knowledge about MPA locations and the purpose of MPAs will be assessed through a short four-question interview. Impacts to rocky intertidal biodiversity will be assessed through non-destructive counts in quadrats and point contacts for common species, plus timed searches of rare species. The biodiversity of each study site will be assessed, and comparisons will be made between rocky intertidal study sites inside a MPA and rocky intertidal study sites outside a MPA. The level of visitor knowledge about MPAs will be compared with visitation rates at each inside a MPA rocky intertidal study site, as well as visitation rates in the adjacent rocky intertidal study sites outside the MPA. The effectiveness of MPAs in changing rocky intertidal visitor behavior will also be assessed. The rocky intertidal study sites include: Dike Rock, Alligator Head, Little Point, Bird Rock, Ocean Beach and Cabrillo National Monument. Pilot data suggests that visitor’s knowledge about MPAs is limited at most study sites with the exception of the Cabrillo National Monument site. Visitors also were observed taking sea stars, mussels, limpets, crabs, and snails at study sites outside MPAs. Although collection of any type is prohibited in MPAs, visitors were nevertheless seen taking abalone, crabs and snails from study sites inside MPAs. The main problems facing these rocky intertidal benches that will be documented by this study are (1) the lack of effective enforcement to prevent poaching, (2) inadequate signage to identify protected areas and fishing regulations, and (3) lack of knowledge about MPA areas regulations on the part of the public. Improvements in management techniques are needed not only at study sites inside MPAs but also study sites outside MPAs to reduce human impacts on rocky intertidal areas.