This dataset represents a high-resolution (1/12° in the horizontal) regional ocean simulation of the North Atlantic, designed to serve as a control run for further sensitivity tests exploring how various changes in surface and lateral boundary conditions impact the ocean circulation in the region. The MITgcm (Massachusetts Institute of Technology General Circulation Model) ocean general circulation model was used, forced by repeated year forcing conditions from JRA55-do, corresponding to 1 May 2003 to 1 May 2004, and lateral boundary conditions from Arctic STate Estimate (ASTE) dataset (Nguyen et al., 2021). This dataset contains information from 15 years of experiments, and does not include 50 years of model spinup. Full 3D U/V/T/S fields and 2D fields containing information about mixed layer depth, sea ice, sea surface height, heat and freshwater surface fluxes are provided every 5 days. The outputs were generated by the University of Oxford under the Natural Environment Research Council (NERC) project SNAP-DRAGON: Subpolar North Atlantic Processes - Dynamics and pRedictability of vAriability in Gyre and OverturNing (grant reference NE/T013494/1).