Understanding ocean-driven melting of Antarctic ice shelves is critical for predicting future sea level. However, ocean observations from beneath ice shelves are scarce. Here, we present unique ocean and melting data from the Amery Ice Shelf, East Antarctica. We use our observations to evaluate common methods of representing melting in ocean–climate models (melting parameterisations) and show that these parameterisations overestimate melting when the ocean is warm and/or currents are weak.