We compiled a database of previously published oxygen and carbon isotope data from archeological, archival, and modern marine molluscs from the Northeast Pacific (32°N to 55°N). Data are from various bivalves and gastropod species. This dataset includes oxygen and carbon isotope data from 598 modern, archaeological, and sub-fossil shells from 8880 BP to the present, from which there are 4,917 total δ13C and 7,366 total δ18O measurements. Database includes the following parameters: paper of original publication, publication year, unique shell identification, unique subsample identification, sample number (given by original authors), subsample number (given by original author), number of subsamples per shell (added here), age in years before present, species, source (midden or modern), latitude, longitude, calculated sea surface temperature (only if published by original authors), tidal height, life mode, habitat, archaeological trinomial (when applicable), oxygen isotope value, and carbon isotope value.