Single-column models (SCM) have been used as a tool to develop numerical weather prediction and global climate models for several decades. SCMs decouple small-scale processes from large-scale forcing and thus allow to test physical parameterizations in a controlled environment with reduced computational cost. Typically, either the ocean, sea-ice or atmosphere is fully modelled and assumptions have to be made on the boundary conditions from other subsystems, adding a potential source of errors. Here, we present a fully coupled atmosphere-ocean SCM (AOSCM), including sea-ice, which is related to the global climate model EC-Earth, consisting of NEMO3.6, LIM3, OpenIFS cycle 40r1, and OASIS3-MCT. <br><br> The AOSCM is tested at three locations: the tropical Atlantic, the midlatitude Pacific and the Arctic. At all three locations in-situ observations are available for comparison. Evaluating model performance with buoy data, soundings and ship based observations, we find that the coupled AOSCM can capture the observed atmospheric and oceanic evolution. Model evolution is sensitive to the initial conditions and forcing data imposed on the column. Coupling several model components while alongside using them individually can help disentangle model feedbacks. Although the model can be extended, we demonstrate that already in the current setup it is a valuable tool to advance our understanding in marine and polar boundary layer processes and the interactions of their coupled components.