The fish larvae (ichthyoplankton) survey is conducted through the California Cooperative Fisheries Investigations program (CALCOFI, http://www.calcofi.org/). These data are a time series of fish larvae counts (or density, as number per 10 m2 of ocean surface) collected in the area of the California Current between San Diego and Avila Beach, California, during the period of 1966 to 2015. Original data were filtered to facilitate consistent comparisons over time and space. The original CalCOFI fish larvae count data is available from the CoastWatch West Coast Regional Node (WCRN) at NOAA’s Pacific Fisheries Environmental Laboratory, http://coastwatch.pfeg.noaa.gov/erddap/tabledap/index.html. The dataset presented here is an aggregation of 31 data files, originally divided alphabetically by taxon (named “CalCOFI Larvae Counts, Scientific Names * to *”). The data were filtered to include only the 66 core stations with a maximum of 1 cruise per season. These 66 core stations have been most frequently sampled in the past and sampling is ongoing. CalCOFI sampling began in 1949. However, the dataset presented here begins in 1966 to include only samples that were analyzed with techniques that apply the most current and accurate identification of larvae to the species level. As the backlog of samples (i.e., before 1966) is re-examined, this dataset will be augmented with that additional, earlier data.