The Ice Shelf - Ocean Model Intercomparison Project (ISOMIP) is currently being proposed as an international effort to identify systematic errors in sub-ice shelf cavity ocean models. ISOMIP will bring together the international modeling community for a comprehensive evaluation and validation of current sub ice shelf cavity ocean models. In the preliminary stages of the project, idealized forcing and geometry are to be used (including physical laboratory data); latter stages will involve realistic forcing and geometry. Model results will be contrasted and compared so as to understand model strengths and weaknesses. This process will be assisted by use of a Live Access Server (LAS) dedicated to ISOMIP. The project will provide valuable information on improving such models as well as likely result in a better understanding of the processes that control the exchange of waters between the sub ice shelf cavity and the open ocean, and hence the role such cavities play in climate and climate change.