Nitrogen and carbon stable isotope data are frequently used to describe the origins and transformations of organic matter. Nitrogen stable isotopes (δ15N) in tissue are used to estimate species' trophic levels, the extent of omnivory, food chain length, and community-wide relationships between body size and trophic level; the latter leading to estimates of predator–prey mass ratios for parameterization, calibration, and validation of food web models. Carbon stable isotopes (δ13C) are used to identify pathways linking producers and consumers and for studies of migration and movement. Collectively, δ15N and δ13C, often with other stable isotopes such as δ34S, may be used to define the contribution of different producers and pathways to consumer production, to assess the trophic impacts of invasive species and habitat modification, and to predict past habitat use, movements, and migrations. Stable isotope data often complement dietary data (e.g., from stomach contents) in food web studies, because stable isotope composition is indicative of assimilated diet over months to years, depending on species, size, environment, and tissue type. There are relatively few large-scale compilations of δ15N and δ13C data for marine species from offshore habitats, but such data facilitate comparative analysis and research into food web structure and function. The data provided comprise 5535 records for individuals of 62 species of fish and squid weighing 0.3 g to 17 920 g and sampled from the northeast Atlantic shelf seas (Celtic Sea, North Sea, Irish Sea, Channel) from 2002 to 2010. For every sampled individual the record lists: species name, date of sampling, position of sampling, body mass, percentage nitrogen in muscle tissue, percentage carbon in muscle tissue, and δ15N and δ13C natural abundance in muscle tissue. Awareness of, and access to, these data should catalyze and facilitate new research with stable isotopes, to improve understanding of marine biology, food web ecology, and human impacts on the environment.