This dataset contains APEX float in-situ measurements taken during the Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) field campaign. Data was collected approximately 300 km offshore of San Francisco, during Spring 2023. S-MODE aims to understand how ocean dynamics acting on short spatial scales influence the vertical exchange of physical and biological variables in the ocean. US Naval Oceanographic Office (NAVO) APEX floats measure subsurface properties including temperature and salinity. Data are available in netCDF format.