This dataset contains the values of natural abundance of stable carbon and nitrogen isotopes in bulk samples and of nitrogen isotopes in amino acids measured in 261 samples of mesozooplankton (200-2000 µm) from a shelf station off A Coruña (NW Spain, NE Atlantic). The samples were collected by double oblique tows between the surface and the bottom with a Juday-Bogorov net (0.5 m diameter, mesh size 200 µm), at approximately monthly intervals between 1995 and 2022. The net was equipped with a General Oceanics Flowmeter for the calculation of water filtered and a depth recorder. All samples were collected between 10:00 and 14:00 (local time) and were preserved dried (60 °C, 24h). Large specimens (particularly gelatinous plankton) were excluded by filtration through a 2000 µm sieve. Stable isotope determinations were made by isotope-ratio mass spectrometry using and elemental analyzer (bulk samples) or a gas-chromatograph (derivatized amino acids) as the inlet device. Parts of this dataset can be found in Bode et al. (2020, 2021) and Garcia-Seoane et al. (2022).