The interface between ice shelves and the ocean is extremely complicated to model, as such benchmark tests that systematically compare results from a large number of ice-shelf-ocean models are crucial. This manuscript presents results from the ISOMIP+ project, documenting the first formal, systematic intercomparison of ice-shelf-ocean models. The manuscript is a valuable contribution to the literature and a benchmark for future inter-comparison projects. The ISOMIP+ project is an important showcase of collaborative science and has fostered model development leading to more realistic ice sheet-ocean models essential for predicting future climate and sea level.